Life's like that! Really?

People: One of those topics I have wondered often on...

I know more than just a handful of them. And many things about them are so difficult to comprehend. Not sure if so many people have a common attitude and common beliefs or is each one different in their own way but have common traits with some group of people. I have certain notions about some things about people. But I am not sure since many of my held notions have broken. I am constantly trying to find out if my notion was itself wrong in the first place or if my notion was right and people have changed by finding other notions to live up to. Notions are so personal to each one that it is very difficult to share with just about anyone around and that just complicates things to get my answer. I am not satisfied with the answer "Life's like that". I want to know why is it that Life's like that? Have people actually done something or made an effort to stop something that they love calling  "Life's like that" ?

"Life's like that!" 

Really? Or is it just convenient that way for people to do whatever they want and use this statement as a justification ?