cough I suggest one pays attention to local cultural norms before following sweeping advice on the Internet. I work in a building full of men in shorts and sandals. None of them are 9 or trailer trash - most of them are 40 year old PhDs. They are fine. Shorts are particularly popular with people who grew up in colder climates. Provided they are a good length (say 10 inch inseam) and casual rather than sporting, there is nothing wrong with them.
Oh and I guess somebody had better throw me out of the sisterhood because I don't give a damn what shoes anybody wears. My only request is if you wear an open toe shoe, like a sandal, please practice basic hygiene and nail care.
[PS. I am talking about normal day dress. I am aware PG has opinions on what you should wear while pitching your startup; if you are pitching your startup to PG, by all means wear what PG likes. If he likes clown suits, wear a clown suit. Geddit?]