I've been doing a lot of therapy recently and am making huge progress. 
What feels like a regret or guilt is being in my 30's and not having a relationship.
I have screwed up or been naive and not seemed out a relationship when someone was obviously interested, me being me just thought they were just being friendly until someone points it out "no dude they were flirting with you." oops.

Now being my age, not having friends a social life and just sticking to myself with a lack of hobbies or interests I feel like I am going to be single for ever and I will moss out on having a family, it feels like a solidified truth and it hurts.

There is someone I like that goes to a mental health meet up at a cafe run by a mental health team, we don't really know each other and to flirt or get to know isn't ideal, I wouldn't want to put her in a position where she felt uncomfortable turning up to the group or putting her off completely, that would be selfish of me.
Its a shame but its fine and it would be inappropriate I'd think, at least I can still crack oneliner jokes to the group, turns out a few find me funny, either that or its just awkward laughter and haven't picked up on it. Doesn't matter I like making people laugh even if its just one or 2.

Point is, it just got me thinking that I will never meet anyone. I don't have a clue socially. 
I just wish I knew how to, how to read signs, how and when something is appropriate or OK to do/say, how to meet people.
I have low self esteem and everything evolved around meeting someone, talking to someone, figuring out if you have a connection by dating, where that will lead etc.
I'm a guy that just goes with the flow expecting someone to just walk into my path and things just develop. 
I just don't get it and I feel like some incel or some sad loser just moping about it in this way.

Well I guess that's my "woe is me" sulk of the day.