How do you handle this?

[CardSharpCook]

In general, just use basic human relations skills. As in life, people will do things that are "wrong". You don't always have to say something about it. Use your judgment to determine the times you should say something about vs. just letting it slide. When you do say something about it, do so with respect. In poker, using EV as your guide is often wise. You can allow -EV violations to occur and not say anything. I think a guy showing his hole cards to his neighbor who is not in the hand before mucking is one such situation. Another for me was a brief dispute over what happened to my $1 SB after there were button shenanigans. My $1 got accedently snatched by someone. Another player at the table was even aware of this. I could see it wasn't worth arguing about, so after a brief, "what happened to my dollar?" I shrugged my shoulders and tossed another chip in. The game was going smoothly, all the players were happy - no need to ruin that by trying to discover where my freaking dollar went.