In my opinion, the biggest faux pas might be claiming absolute knowledge about anything.
In a tech environment, even if you're 100% confident about X being true, you express it with, "I think X might be true" or, "Let's try it with the assumption of X and see if it works," so that you allow room for the possibility that others may contribute something you did not think of.
Image: FLICKR, PHIL WHITEHOUSE
