I’d focus on the fact that this just wasn’t working for you. It doesn’t even matter what good sides he has. This isn’t working for you. That’s all what matters.

As about improving or changing it’s pointless to enter relationships in hopes one changes. I mean it’s a guessing game. Most people don’t change but what a waste of time entering relationships with people who require change and then guess if they’ll change. Why? They are who they are.

Yes being invited to a concert and then learning that the person sold the ticket without even giving you heads up is extremely annoying. I’d not be happy. I’d just chuckle it to the fact that you don’t know this guy. Talking on social media isn’t really knowing someone. Many of these men are married or in a relationship yet go to these things alone and shamelessly flirt and try to hook up with women. He likely got in trouble with his significant other for inviting random women to concerts and he was forced to get rid of tickets. “Things got weird” likely means variation of that. He’s not a big loss. I sure try not to feel guilty. You likely dodged a bullet with this dude.

I don’t know. Most people are reliable and reasonably stable imho. You just have to get to know them and watch for red flags. Whatever happened to your avoiding this particular crowd? Your perception of people is likely skewed by the quality of people you associate with. Plus in general drinkers and stoners are not very reliable and certainly aren’t stable just due to the nature of substances they consume.