I like to keep winning lottery tickets on my bulletin board.
First, it shows that you’re a lucky person— and people always need a lucky friend. They hope that the luck will rub off on them, and will want to keep you around.
Second, it shows that you’re rich, and money is no problem for you— in fact, it’s so unimportant that you feel no pressure to turn in winning lottery tickets to collect the money. You literally have free money hanging on your walls. People will recognize wealth as power, and power attracts people.