Do people actually tell you what they are like by declaring what they are not like at the beginning of relationships?

When I was still working, on one of my last projects we had a project manager and he gathered us around and one of the first things he said in the group talk was “I’m not aggressive” yet he turned out to be the most aggressive, bullying arsehole in history.

A women I recently had an online relationship with said to me early on “I don’t play games”, yet turned out to be a massive game player…