Will you expect someone to say sorry?

Or you just let him/her go?. Take my experience as example,it was a day when a girl stepped on my shoe,I know it was an accident but after that incident she quickly turn back her face,ignoring me,talk to her friend,and acting innocently hoping I wasn’t aware. I know it was only a small accident and not really a big problem(Actually it was my old shoes,and I’m an apologetic kind of person). So I let her go,but something I can’t accept is her behavior. Another experience,a man was running in rush and he hit me on his way(I wasn’t fell off),after that he just keep rushing on his way just like I wasn’t there. If this situation ever happen to me again,do you think I should expect that person to apologize?(I know it was an accident and not a big deal). If this situation happen to you what will you do?,will you judge him/her from her age,background,sex,relation,rank,companion(sometime someone in majority/powerful companion will make us feel intervened),or else, before you expect him/her to apologize?.
I wonder why some people do that?,is that because they don’t know what to do?,too scare to admit it?or just simply ignorant?.