Are long coats ever acceptable (say in Winter) or do they invariably end up making you look like a weirdo in a trench coat?
Guess it depends on who you are and what your doing. A guy going to work in a suit obviously looks normal, a basement dweller buying action figures whilst wearing a stay calm t shirt looks like a weirdo
The only reason where a coat is necessary is winter. I don't see what could go wrong if you are able to put together a coherent outfit with good clothing choices.