I just want to say that sometimes people aren't bragging when it sounds like it. Sometimes they are socially awkward or they are trying to create a human connection (or both). Sometimes they just don't know how to do it or realize how it comes across.
Someone: I like cats
Me: I once trained dogs in Brazil.
They are like OMG really? What does that have to with cats, but in my head - I was like cats --> animals --> dogs --> I once trained them --> Maybe they will like this and think it's neat and I can make a friend.
Bad example, but the idea behind it hopefully comes across.
A lot is text and we come with our own prejudices about how things 'come across' that the other person in no way intended. We just make assumptions based on our moods and other things when the other person is legit just trying to form a connection. Connections are hard. Finding your tribe is harder.