Dress up - not down for Mass.
Remember, it's summertime - one should be properly dressed for Mass. Cathy at Recovering Dissident Catholic has a terrific post on the subject. (Seriously.) It's a follow-up to her internationally acclaimed post on what some people wear to Mass on Pentecost - I can't even say what that is. (Her previous post, "Gang Colors At Holy Mass" garnered a spot on Fr. Z's blog!)
[Photo: John Paul II after receiving the Offertory gifts from a semi-naked woman in Papua, New Guinea, 1984.]