I'm going to agree with everyone in this thread that the thread originator prefers the company of gentlemen, but one thing, and this is an understanding of mine, so feel free to correct me... But
The phrase "first impression is everything" isn't saying the first impression is what you SHOULD go by. It's not advice for the impressee, if you catch my drift. It means that most people are impatient and will likely only LOOK at the first impression, not that they should, but they do. You seem to be using this expression as a defence for judging a raid by one boss, but yeah. It's not advice to go and take everything from a first glance. Obviously, that's a bad idea.