[squarefoot]

European here. I usually stay away from people who smile with their face but not their eyes; that's a sign they're not sincere. I mean not the half smile put there just to avoid a neutral expression, but a smile that attempts to appear warm and deep while it's not. Especially at work, the more the people I met who were good at it, the more I did my best not to have to deal with them, because to be good at it they must have trained it, which to me spoke volumes about the person.

[xnyan]

As an aside, if you want to make a genuinely warm smile but are not feeling it, this trick usually works for me. I think about my partner, or a beloved childhood memory, or something else along those lines. I just close my eyes for a second and focus on that, then let my face smile while I think about the happy memory.