One that really makes my blood boil is when, you have permission to hunt a piece of private property and a few others also have permission. You are set up and hunting and one of the others that also have permission takes it upon himself to become the property police. Walks over, busts your set up, and wants to see your permission slip. Had this happen while working a hot gobbler and had him at about 80 yards and commited to coming in. The outcome was NOT good for the idiot, to say the least.
IMO, If you have permission to hunt a piece of private property, and you know that you are NOT the only one who has permission, mind your own damn business while hunting there. Have the common sense and courtesy to politely and quietly avoid a fellow hunter if you mistakenly walk in on them.