I enjoy a social meal now and then, if the people are nice and I feel good around them.
If I'm eating out, and it's Chinese, Indian, or Ethiopian, where the tradition is many dishes and everyone has some, I can do that and it's fine - but then the food comes in a large bowl or platter with serving utensils, and everyone helps themselves, same as one would do at a family dinner at home (pass the peas).
I will not do the plate sharing, food sharing, everyone takes food off my plate thing with people. It feels like a boundary invasion. It's too intimate. I don't want to be that intimate with anyone but my nearest dearest.
At lunch with work colleagues I actually stuck my hand over my plate to force someone pushy to leave my food alone. They got huffy, and I just looked at them* and said, "I do not like it. AT ALL. When people do that. Do not do that. Thank you."
*actually I gave them what an old flame used to call The Laser Glare Of Death. Apparently I glare pretty well when the need arises. 
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"I believe you find life such a problem because you think there are the good people and the bad people," said the man. "You're wrong, of course. There are, always and only, the bad people, but some of them are on opposite sides."
-- Terry Pratchett, Guards! Guards!