Gifts.
I am poorly organized and I never know what to buy people. But when people give me gifts, I feel obliged to give a gift. But I don't know what to give people, and I'm terrible at planning and organizing and shopping.
Giving me a Christmas gift is a nice gesture, but it makes me feel bad because I'm not prepared to reciprocate. I would prefer for that reason that people don't give me Christmas gifts.
Same thing for my birthday. I can't keep track of everyone's birthday and remember to get gifts. And then people end up offended that I "forgot" their birthday. So maybe let's just not do birthdays, ok?
So please, no gifts for me. You will make me feel bad because I don't have any idea what to get for you, or time to go to the store and get it, or the organization system to keep track of people's birthdays.