1) Not understanding the need to separate the logical from the physical. The application is not the database and vice versa. The application places requirements on the database but these are unlikely to be the full set of requirements on the database.

2) NOLOCK - I have previously worked at a multinational that had it as a coding standard requirement (not guidance) on *ALL* SELECT statements. Yes, there is a rather large amount of financial transactions involved. Muppets.

3) Difficut to maintain: terrible code, no/poor documentation and no strategy. Brilliant. [Yes. That is sarcasm.]

EDIT: I couldn't count up to 3!!!