Putting your bare feet up on the table is not good. And I've seen it done.

Coughing/sneezing into your hand and then handling the chips.

Eating greasy food at table and handling cards and chips. And picking your nose.

Vomit on the cards and chips.

Never seen anyone boot on the table. Beside the table yes - on it, no. I have seen the coughing stuff. Go to the arm and back of elbow, not the hand.

Yeah, nose picking not good.

Chronic belching and farting. I hate seeing chips melt.

Don't forgot not showering for a couple of days. That's never good.

Never lick your opponent unless they ask very nicely.

Scratching yourself is frowned upon.

BACKSCRATCHER!!!

Pee. And I've unfortunately seen that happen too.

I've found sniffing glue and taking amphetamines is frowned upon in most establishments.

No one said flossing/picking your teeth? God, I hate when people do that at the table!