I just can't imagine having to come to terms with the idea that this is it after believing that there is an eternal afterlife and that I will one day be reuinited with my loved ones. It has to be a huge disappointment. I think that this could encourage resentment.
That is an awfully broad question that could lead many places. Like everyone else, I was born an atheist. Unfortunately, I was then indoctrinated into a mainstream Protestant faith. I began the process of escaping this mind virus in my early teens, but I was probably 15 before I could admit to myself that I didn't believe it at all. I often wonder how I would have turned out if I hadn't gone through this indoctrination. But I suppose I ended up alright and should be happy for that.