After thinking about this for some time I came to the following results (my own answers to the questions):
Again: Thank you all for the variety of opinions and reasoning on this topic.
- Indeed, it is theoretically possible to find reliable friends. It is theoretically possible to win the jackpot by buying a lottery ticket as well.
- There are probably no general warning signs.
- The only option is leaving bad (not-)friends → If this is possible. There might be reasons of overriding importance. This is a decision which must not be rushed.
I give up. It’s not worth the effort: Actively searching just too be disappointed while hoping to gain something. Never gonna allow anybody getting near to me again.
For the previous friendship: Time to burn bridges. Play time is over. This ends now!
They will never, ever understand or accept anything. They will never, ever question themselves and will always think they did everything right and did not hurt me. Why bother?
While I understand your personal conclusion, I will say that, if you're typing this fresh off of someone wronging you or something negative, that this sort of "I'm just gonna shut myself out and never put in the effort again" is usually temporary, in my experience. We all need some private time after someone you spent a long time with turns out to stop texting, refuses to respect your wishes, or doesn't think they can do any wrong, etc..