I suppose it's best to go for black? I saw a nice pair of closed Birkenstocks but they're white with a pattern on....I guess they won't go with anything! Crocs seem a bit clunky for the office, although some of my colleagues do wear them. Are the Birkenstock clogs less so? Not sure what to look for tbh, shoes always look large on me as I have big feet. I usually wear dark jeans or dark linen trousers.