I am a high school teacher and while we don't really have a dress code (other than "no open backed shoes") I guess some common sense applies. As some have mentioned, a pre-k teacher doing hands on activities, a gym teacher, etc. might want to wear something more casual than the rest of us! I would definitely wear my Disney
crocs sometimes if I taught the little ones!
However, I do think that what you wear is important, especially at work or an important occasion like a wedding or funeral. Respect is conveyed by how we speak and dress for these occasions. Sweatpants to a job interview is not okay!
I don't really feel comfortable in a suit or a skirt,esp. when it's so hot hte first few weeks back, but I do think it is important to dress professionally. 90 % of the time I wear dark (black, brown, gray, navy) pants with a sweater or button down shirt and medium heels or ballet flats. When I taught summer school, I wore a polo shirt often, because we had no air and it was hot. Khaki's are fine, but I am pear shaped and light colored pants just really emphasize my "problem".
I've worn dark, trouser cut jeans with nice heels to work and no one really noticed they were jeans, but mostly I save jeans for the "wear red for heart health" or "wear pink for breast cancer" days where we donate $ to wear jeans.
I wouldn't wear flip flops, sneakers, faded jeans, t shirts, shorts, etc. BUT I find the worst violations are the few teachers who just wear clothes TOO tight or TOO revealing (can see underwear through dress, or can see lots of cleavage, etc.) 98% of teachers dress professionally, though, so I guess we don't have too big of a problem. Oh, and definitely NO velour track suits!
Actually, there is one exception to what I said about shorts- I have a navy blue suit that is short sleeved and has "shorts" that go with it- but they are cuffed, creased and hit below the knee, so I've gotten nothing but compliments on that and it looks pretty professional.
HTH!