Is it normal to not want to know people better/get too close to them?

Is it normal not to want to know people? As in, not to want to get to know them better and instead just keep them in mind the way you think they are? I am friends with a lot of people on facebook i dont know personally. You know how it is - you find some celeb from your childhood and you add them - or someone you think is cool through some internet facebook conversation or a friend of a friend etc - but then when you dig through their lives and find out more, you realize they are not the people you thought and actually quite disappointing so you wish you had never known and could keep that illusion? I am going ot film school so some of my friends are former child stars or some guy on Star Trek who had a minor role and i really liked them as such but obviously things have changed and its been a decade or two or 3 with some and you realize they are so not what you expected. Some of them are right out assholes (not to me but in general) or losers or freaks or they are conservative nut jobs and bible reciting crazies etc/ - and you realize you wish you had never known. Like take Nathan Fillion, for instance, i follow the guy on twitter and he is an ass. He always makes snotty, condescending remarks and is kind of a dick. A total turn off and it is sad becasue i like Firefly and i wanted ot like him but he is terrible. He sucks.

I guess I just realized that a lot of people are better in the abstract. The less you know about them, the better it is. So i dont really make an effort to get ot know people better or find out, as i dont want ot be disappointed and have a low opinion of them. I'd rather just remember them the way I do. Is that normal? I noticed that in general in life too - i am often more in love with the idea of someone, the abstract, than the real them. Do others ever feel this way? I am often worried about getting ot know ANYONE better out of fear that they will just turn out ot be assholes.