Hello ch12, Just because people weren't rude enough to comment on your clothes, that does not mean that the other people didn't notice.
Perhaps reading a bit on how others feel on this subject would give you a different perspective. Take a look at this recent thread. You'll see that some people agree with you, so it may not convince you to dress up before attending the dining room on formal night, but at least you won't think that other people don't notice.
<http://www.cruise-addicts.com/forums/read.php?24,1211006,1213375#msg-1213375>