I used to work at corporate.
They used to try to convince you that it was the most prestigious place in the industry to work at, which it certainly is not. There's a lot of people who have been there forever, so they're very jealous and insecure of new people who come in there, so you're treated as an outsider.
People dress casual. Some people get together, it's pretty "clicque-ish", so the clicques get together. Very high school maturity level there.
My day was to go in, do my work, and leave afterwards. It's one of the few companies I would never consider returning to.