Puzzles+And+Riddles

Here are some riddles for you to solve, but if you find the answer, put it in discussion.

1. Their is a man who lives in the 12th story of a hotel, and after work he takes the elevator,if it rains or someone is on with him he goes straight too the 12th floor, but if it doesn't rain or he is alone he goes to the 10th floor and walks up two flights of stairs,why?