In my opinion the gamma function is by far the stupidest. IME, the off-by-one literally never makes equations clearer; it only obfuscates the relationship between continuous and discrete things (etc.) by adding in an annoying extra step that trips up your intuition. Seems like simple coordination failure.
This thread is for asking any questions that might seem obvious, tangential, silly or what-have-you. Don't be shy, everyone has holes in their knowledge, though the fewer and the smaller we can make them, the better.
Please be respectful of other people's admitting ignorance and don't mock them for it, as they're doing a noble thing.
To any future monthly posters of SQ threads, please remember to add the "stupid_questions" tag.