I still like to dress-up. For my 4 year old - teh best part of a cruise is wearing a party-dress every night.
It won't ruin my dinner, if I'm dressed to the 9s and you are at the next table wearing cut-offs and flip flops.
My daddy always said it was better to be the best dressed person in the room than the worst dressed.
On Sovereign last fall, a young guy in his 20s was turned away from breakfast in the MDR - he was wearing a muscle shirt and a baseball hat.