Is it normal to write stories about people i know?

People are usually adamant about reading my stories, not because they actually like them, but because I tend to use people that I know in real life in my stories (only I change the names and some of the details about them so that they can't figure out so easily who inspired what character). I've written some pretty wild stories about some pretty inconsequential things I've heard or seen in real life and the fact that I use real people in my stories makes it all the more interesting to write them, plus I think it makes my characters more realistic.