Hello, p.q. I laughed at your comment, "Oh yeah it does help if you don't pick your teeth..."
On our first cruise ... on Princess, no less! .. we actually had a tablemate who did that! Not with a knife, but several toothpicks, which seemed always to be hanging from his mouth. He did a lot of other boorish behavior, too...
But I'm with you -- It is nice when people get dressed up...but it is nicer when people are clean and tidy, and pleasant conversationalists, and don't complain incessantly about how *other* people are behaving...
We wear "Sunday goin' to meetin'" clothes...but not formal tuxes. I think we look reasonably respectable. Although I'm not always sure my husband's shirt is indeed properly tucked...
(I wonder if that's where "tuxedo" comes from...the cumberbund thing hiding the fact that guys rarely "tux" in their shirt?? )