Met lots of celebrities, including three (almost four) US presidents. Spent a summer at a Congressman's summer house on a lake. Met plenty of famous musicians and a number of actors/actresses, and spent time with a few of them. They are just people like everybody else; many are very nice, some are not so nice, just like you find with any other group of people.
I have some sympathy for what they go through, though: back in the early/mid 1980s, I did some acting in a few TV shows here in Hong Kong. On one of them, just before Chinese New Year, I raped a woman and then killed her husband in a rigged (I cheated!

) sword fight, and insulted the Chinese people [they never let white guys be the good guys!]. That show had the highest viewer ratings of any that year, with more than eighty percent of the population watching it. When I went out on the streets after that, EVERYBODY would look at me, point at me, whisper about me. etc... At least people made a distinction between the actor and the role, and no one was negative about it. The attention was so strong that most of my friends wouldn't go out with me for a few months afterwards, until things quieted down a bit. Gave me a little taste of what real "celebrity" must be like. Frankly, although it has its advantages (you get good seats at restaurants, discounts at shops and generally better service everywhere), I'd rather be plain old anonymous me, able to walk around in casual clothes and scratch my nose without someone staring at me and gossiping about it.
Of course, since I recently started hosting my own weekly TV show segment here, and the station seems to be plastering my face all over the screen during the week advertising the show, I might not be so anonymous for too much longer...

Fortunately, it is on the less-watched channel, so the effect isn't TOO bad, at least not yet.