Definitely the time when already had the job and had been getting no negative feed back or anything, then suddenly half way through the third month of my three month probation "Yea, we're not keeping you"

I once worked for a startup and I got hired at the same time with another guy. That guy was fired at the end of his 3 months probation. On the last day, at 6pm right when he was about to go home...

They said something like he wasn't adapting and he was stubborn. In other words he didn't want to do overtime or follow their old mentality.

I got out of there when I reached one year because it was my first developer job and I needed the experience... None of us ever regreted leaving that place.