Thats why I choose to be a pessimist. It eliminates disappointment.
Expect the worst from humans and you'll usually end up being factually correct, you'll never be disappointed, and occasionally, if the moon and the stars align, you just might be pleasantly surprised about something at some point in your life, just don't count on it.
Optimism looks fucking exhausting when dealing with our gem of a species. Being let down most of the time and still putting on a smile for the next disappointment you won't expect 5 minutes later. Looks like masochism minus the sexual pleasure. Good luck with that optimists!