I say this with respect: the kind of attitude you're describing does more to isolate people than anything mentioned in the original post.
Bitterness or even just muted disappointment will drive people away more than any of the factors you mentioned, by a factor of 10. Have any of you gone on a date with someone who looked great on paper, but seemed unhappy to be there or resentful towards you? That's the ultimate connection killer.
You can have all sorts of setbacks, but if you're chill and have a good attitude people will want you around (barring a few assholes, but it's important not to worry about them). OTOH even if you're very good looking, no one will want to approach you if your vibes are bad or inward facing.