✔ 最佳答案
If his negativity is really getting on your t its, get on his by being extra extra happy, smiley and positive around him all the time.
When he annoys you by saying something really down, compliment him with a big smile and constantly give him positive remarks about whatever it is he is moaning about.
It will annoy the hell out of him and perhaps with a bit of luck show him sarcastically just how boring his negative attitude is and it will show it up extremely. Let him know that it is just plain tedious and the more he does it, the more it makes him into a drab, annoying individual that warrants no attention.
Lean into his face real close and say 'have a nice day, wont you' instead of responding to his pessimism