The pressure to present as attractive is sometimes too much. I say exercise your right to wear whatever the hell you want. At least once a month. This is serious psychology, girls.
Oh, it's so sad...she's really let herself go.
Live the slag thing, even for little bits of time, let your hair resemble a bird's nest. Put an insane slant on it by saying, "Gee, I do believe I'm the prettiest girl here today". And let 'em talk.
That's not to say it's not a grand thing to walk out one's door looking and feeling 'presentably' fabulous, but I'll leave that up to your own good taste and sense of style.
You know you have it.