I can't believe I'm replying to this, but. . .

Q: Why do people feel the need to post a thread asking a question when there are already 2 threads on the front page asking the same question.

A: They're too lazy to read the first page of posts for an answer to their question. In addition these questions are rarely well thought out or phrased.

To your point about real life, if my friends asked questions as dumb as many of the ones posted here, I would respond with a facepalm and please tell me you're joking. If a stranger asked questions that dumb, especially repeatedly, I would probably endeavor to avoid that person as I don't enjoy their company.