For the most part I agree with Miss Manners, though I will tip even if I lost if the dealer is very friendly/fun. For me, the people at the table and dealer is what makes it fun.

When I play blackjack, paigow, and the other table games I tip more if I am winning (usually ask them if they want me to bet it for them). As long as they are nice/friendly I try to tip the dealer at least a $1-$5 if I have been sitting there for awhile, whether up or down. I generally won't tip if I am bad salty streak, though. If the dealer is rude or not even trying to be personable, I generally don't tip them, even if I am winning. When I play poker, I only tip when I win a pot, usually a $1 or $2, up to $5 if its a large pot.