Some consultants walk in like know-it-all supergods and present their 'perfect solution' before even taking a millisecond to understand the problem.

These types will get NO respect from staffers.

Additionally, there are often very good REASONS that certain things are done certain ways -- reasons that take more than a couple of days on-site to understand.

Some consultants come off like real idiots when they realize they've missed something really basic that everyone else at the client site knows, but that they may have overlooked.

"Hey Dr. Genius, don't you think we already looked at that solution 3 years ago, but since system x connects to system y through z it can't work."

The client's staff may not be as stupid as the consultant thinks...