Sharing tables with strangers is completely taboo in most areas over here. The only time it is acceptable (in my experiences) is when it is a very large booth, and you can share the table with someone else while not having to look at them.


--------seating----------
Person A Person B
[========table===========] This is acceptable


--------seating----------


--------seating----------
Person A
[========table===========] This is unacceptable

Person B
--------seating----------


Thankfully I never have this problem, because hostility comes off of me in a figurative aura, and people generally avoid looking at me. I generally think I look friendly, and people avoid eye contact or ask me what is wrong. It's perplexing, but saves me a lot of small talk (I hate small talk).