Peeking inside the forbidden windows

Is it good to read other's thoughts or their capabilities? Doesn't it upset them, yes it does, of course it will. Go peek in someone's private room, he/she will beat you to the pulp. Everybody wants to have a private life, keeping his thoughts, doings, some peculiar habits veiled from the world. But what if someone elaborately studies them, reads them, unveils them? Then why do people do that? why some people find it interesting and rather adventurous? In some way, isn't it close to stealing, getting onto someone's private property and checking out their very personal love letters, private bank account numbers, etc.
You call them subjects, you call it study, I call them people, I call it stealing. There has always been a limit to be maintained, precisely, a limit after which your so called 'subject' doesn't feel naked in front of the world. My 'people' have their private life and their private life is not meant to be peeped in.