So, some surprising facts about religions that actually exist, facts that some people that debate religion in the public sphere repeatedly fail to realize, so in a way this is a list of attested traits in real-world religions:
This is badly organized, and a fair share of it is kind of aimed at highlighting differences between Christianity and one of its closest relatives. I have very little about Dharmic religions in this - and the only one is really the love-child between Abrahamism and Dharmism anyway, so ...
there are religions that conceal some of the religion's beliefs from a large segment of their members. (e.g. the Druze religion)
there are religions which one cannot join at all. (druze, mandaism, some varieties of zoroastrism - also, one "subethnic group" in Judaism doesn't perform conversions, but recognize converts through other subethnicities of Judaism as valid Jews.)
there are religions who restrict which outsiders can join: Samaritanism only permits Jews to convert, Christian Identity only permits whites to join (and some varieties teach that non-whites lack a soul, that Jews may be the physical offspring of Satan, etc), Nation of Islam does not accept whites.
there are religions in which the concept of joining isn't even really relevant, as member lists or ideas along the lines of a member aren't even a thing. (some shamanic religions.)
there are religions that will try to dissuade potential converts from joining. (e.g. Judaism).
there are religions that do not think non-members will go to hell. In fact, the majority of religions probably don't even have the classical Christian idea of a hell.
there are religions in which belief isn't really an important thing, but rather actions or even community (some consider ritual action important, some rather consider some social things more important, although often in religions that value ritual, the ritual is a social thing; exceptions do exist, of course. But an example of social ritual: In Judaism, it's considered important to pray in a group, because it helps build a Jewish community. Likewise, various strictures and leniences wrt the kosher rules, some potential leniencies on shabbat rules, etc, serve to cement a community, and possibly even makes maintaining a community a by-product for whosoever tries to adhere to those rules.) Of course, there's also non-social rituals: in a way, the wearing of tefillin in Judaism can be seen as a non-social thing as it does not contribute to the community in any obvious manner (otoh, tefillin cost a lot and can only be written by educated scribes - so in a way it helps maintain a scribal subculture that keeps writing other things that help maintain the jewish culture ...)
in some religions, believing doesn't make you a member: you don't become a Jew, a Zoroastrian, a Yazidi, a Mandaean, a Druze or a Samaritan just by believing in those religions. In a way, it's a bit like religious orders in Christianity: you don't become a Jesuit just by believing in Catholicism. In Judaism at least, non-Jewish believers have a designation, and were widely counted as non-Jewish adherents in late antiquity (until Christianity became state religion in Rome) - a less stringent religious law applied to non-Jews, and a non-Jewish believer that wanted (or wants) to take on the full yoke of the Torah can do so - much like a Catholic can decide to take on the yoke of some religious order (such as becoming a monk or a cleric - which unlike layman Catholicism require abstention from marriage, and various other strictures).
In some religions, the clergy have a sort of special position vis-a-vis God, e.g. the Catholic and Orthodox cleric (and also in high church protestantism) can perform sacraments a non-cleric cannot - so in a way, in these faiths, it's held that the cleric is granted some powers (but also of course, responsibilities) by God. In other faiths, the clerics can have quite different roles.
Many Christian countries have legislations that assume the cleric is needed when performing a wedding - the marriage is not valid unless the clergyman has declared it so. This is not the case in Judaism, for instance, where the wedding is a contract between the two, and is considered valid by Jewish law as long as the contract is signed by both and the signing is witnessed by valid witnesses.
So Christianity-influenced secular law has kind of forced the rabbis in some countries to be present and say words to an effect that Jewish law does not call for.
What is a rabbi then if he isn't a priest-like conduit of sacraments? He is supposed to be a scholar of Jewish law and customs - a go to guy for questions regarding Jewish things. Any Jewish male over the age of 13 (in orthodoxy - in conservative judaism and reform judaism women are also included) can lead the congregation in any ritual (in orthodox judaism there are some rituals that should be led by women though, such as lighting the shabbat candle and such), as long as he knows the ritual. Rabbis are of course expected to know the rituals, so they end up performing them if no one else knows the drill. In a way a rabbi is a lawyer of Jewish law as well, and there are different degrees - whether one can lead a court that can judge cases of certain degrees of seriousness.
Sunni islamic clergymen seem to occupy a rather similar position visavis their congregations, whereas some varieties of shi'ism seem to be more similar to Christianity as far as this goes. (But I can not guarantee this to be the case.)
Of course, in some religions this position comes with added responsibility. (E.g. the rabbi is expected to adhere more closely to halakha than his congregants.)
Then again, in Judaism too there's been a development towards the congregation leader as a middle-man between God and creation - in Chassidism, the rebbe/tzaddiq is in practice seen as an intermediate.
the protestant focus on scripture is unusual in religions, even among Abrahamic religions! E.g. in Judaism, Catholicism, Islam, Orthodoxy, Zoroastrism, etc, a lot of the idea of what the religion even is comes from extra-scriptural traditions. Of course, even the Bible as such is defined by an extra-scriptural tradition, how to read and understand it properly often is a sort of by-tradition, and any cursory look at any protestant group will find dozens of things they consider important for a proper Christian life that nowhere can be found in scripture. (so, this is also an important thing about religions: the members' view of how the religion works and where it derives from and why one does so or so and what one should do and why may very well diverge quite far from the history of these behaviours.) More concrete example: there are people here that have been shunned by their religious friends for moving together before getting married. In earlier times in this area, only nobility got married the way one currently does - MOVING TOGETHER was recognized as a valid marriage. Priests even *refused to perform weddings for the yeomanry and peasantry*, but after some time, started to accept performing weddings somewhere else but DEFS NOT in the church, and after a century or so even peasantry was accepted to marry in the church. Nowadays if you don't go through that hoop, you're not considered married. Of course, this is nowhere mandated in the Bible, yet these sola scriptura people think it is. Funny that!
(NOTE for moderators: this isn't a religious argument, it's an *attestation of a religious behaviour* and an actual justification of why this behaviour shows that they are inconsistent - I do not judge their behaviour, I only note that it is inconsistent. Everyone, of course, is inconsistent to some extent and they could probably point out inconsistencies in my behaviour if they scrutinized me carefully enough.)
Scripture has quite a different role in, say, Sikhism, where it's read as a kind of devotion - and not as a study to figure out doctrines. In Judaism, exegesis of a kind similar - but rather trickier at times - to that in Christian circles does exist, and probably is the source for the Christian way of reading scripture. Only, in Judaism the exegete goes about it quite differently, and has somewhat different sources for the exegesis. (E.g. talmud, the targums (translations to aramaic that paraphrase and elucidate the text) and midrashes (inspired by the targums, a kind of targum without translation - elucidation and insertion of tangents to the text, etc), mystical writings, gaonic writings, unwritten tradition, ..., but c.f. Christian use of patristic writings, medieval and newer theologians (Aquinas, Duns Scotus, /Luther, /Calvin, /Zwingli, /Hus, ...), early translations (vulgate, peshitta, church slavic, LXX...), mystics (Luther was inspired by Meister Eckhart, for instance), and unwritten traditions.) Often, when the Jewish exegete reads sources, he looks for a halakha - a ruling on a practical matter. OTOH, less legalist exegesis also exists, but that often consists of trying to understand how many layers of metaphor some mystic or talmudic sage or gaon has hidden a nugget of wisdom behind in order to make people have to seek it out. In a way, the effort of coaxing things out of the text is a kind of highly abstract ritual, and a way of keeping a discussion with earlier Jewish theologians going. It's a participation in a millennia-spanning debate.
In Judaism, studying such things is considered one form of prayer!