How was your_______...

This isn't so much of a "what grindz my gears" but more of just a thought.  

Why is it that after a holiday, vacation, or the summer, people always seem to ask you how was it?

I know that it is being polite, however, do people really care?

I have had many people tell me that they didn't care, but they were just accustomed to doing so.  I also know that there are some people who I ask, and I really care how it was, and then there are others, who I ask just because I also think it is the right thing to do.  

Is this just a custom in our society, to try and avoid awkard silences, or are there a lot of people out there who genuinely care, that I just don't know about?