Fun topic... Right side. Always, unless nothing else is avail in First. Then I get less picky ��There’s always something avail on the right in C+ on my business routes at booking and I tend to select 7C or 11C depending on plane type. No good reason I can think of except maybe habit. Flew 2C on 13 of the last 16 flights. 3C on two and 1F on the other (that last one was United, A320)