ot: do you think someone is insecure or lying?

Probably a combo of both for the most part. Same when you're talking to someone and they just volunteer info about their sexual conquests. I don't find it impressive and I didn't ask.

Plus, with the money thing, that's one of those things that friends shouldn't get into. Like, you'll know if a person does well or not, generally speaking, but when friends start to know exactly what you're making, it just inevitably leads to awkwardness. One of my closest friends, who as of a few years ago started doing really well, would openly talk about what his bonus was that year. He wasn't lying and he's not insecure, he was just excited about it, but almost immediately afterwards, if a bunch of us were out for drinks, someone would basically ask him to pick up the tab, knowing he could afford it. Aside from the fact that the person asking was a dick for doing so, it's an easily avoidable situation.

That's a huge part of the reason why I always use an accounting firm where none of my friends or networking colleagues work to do my taxes.