I'd just like to throw in a few cents here:
1. Notability: Pathetic. Verifiability already keeps out junk, why do we need an icredibly subjective set of guidelines based on some old essay?
2. RFA: Don't expect any second chances here. Made a copyvio four years ago? Too bad. Don't use edit summaries 100% of the time? rejected. Don't vote on AFD? rejected.
3. Not written down, but the community isn't very forgiving for past policy violations or for little slips. If some admins out a bunch of pressure and provocation on a user, if they go a little batshit in response, then they can't wait to block them. This is also why RFA is bad: Genuinely good editors get rejected, bullies stay in.