I have always maintained that 95% of the music business makes it incredibly easy to be kind and courteous to them at all times.
Unfortunately, our reputations are not based on how we deal with the 95%. Our reputations are based almost exclusively on how we interact with the 5%.
The people who are easiest to work with in the business get along with everyone all of the time. They get along with the considerate people and the not so considerate people. You won't win any points for dealing well with them. Everyone does.
It's the people who always have opinions about every rehearsal or gig that they then offer up to the room unsolicited. It is the people who don't pitch in to fix a crisis that might arise on a gig because it is not specifically their job to do so. It is the people who criticize others while not worrying about their own playing or behavior.
How we deal with these people is what our reputations are based on. Fair or unfair, this is reality. I find this is a good thing for me to keep in mind when I'm debating whether to let someone know they are in the 5%, no matter how tempting that might be at any given moment.
So when you encounter someone in the 5%, if possible, view it as an opportunity to solidify your reputation as someone firmly in the 95%.