While I agree about Boarder Drama (having worked in a couple barns), there’s a flipside:
BOs who really shouldn’t be in the position.
Examples:
1-Friend whose late husband was apparently the one with the knowledge & horse smarts.
When I first met her & her friends/workers, I thought “Great! When having my horses at home becomes too hard, I can board here.”
Now, some 7yrs later, you could not pay me to leave a horse at that barn.
Care is not criminally bad, feed is adequate (though insistence on alfalfa mix hay doesn’t suit my horses), turnout is less than I like w/weather as the excuse < though my 3 are out happily in what they consider unsuitable.
Main problem is what friend laughingly calls her Board of Directors. These are long-term boarders whose knowledge of horses is sketchy & sense of entitlement huge.
One gal called the BO, when we were out having dinner, to report trough heaters weren’t working because “outsides aren’t hot”. She was referring to the cages that protect the heating element 
If those had been hot, the heaters would have indeed been broken!
Another member if the Bd - with perhaps all of 10yrs experience w/horses - is a self-proclaimed NH guru.
When stall cleaners had a problem with handling one boarder’s horse, idjit took it on himself to “train” the behavior. Without saying a word to the owner. WtheEff?!? 
Another’s specialty is annoying the boarders, she’s been “fired” by the barn vet for meddling & is a wealth of No Knowledge.
I found her in tears at Fair one year because her mare was acting “crabby”. I took one look & it was obvious mare was in season 
Can we say “winking”?
Last member of the BD is sweet, well-meaning, but failed to recognize an obvious choke.
She had fed horses before joining us as we were having dinner at BO’s.
Reported “green stuff from his nose”.
Owner was Annoying - who had no interest in leaving the table to check her pony.
After dinner I suggested we look at him, found him w/definite choke.
She then was hesitant to “bother” the vet.
I strongly recommended she do so.
Vet came, tubed pony to resolve the choke.
2-New owners of longtime boarding barn - Dr. & Lawyer.
Neither has owned horses. From their website it seems the boarding business is but a small part of their Green Acres vision for the property.
I visited with friends considering moving their horse. Barn reeked of ammonia, looked the same as when I’d boarded there 22yrs ago.
Brand new indoor was built downhill from the barn. So in Winter you’ll be skating your horse there to ride.
Noone was present on the property save the BO Dr. who, when asked if stalls had been cleaned, or if anything would be done to make that downhill path safer had the same answer “Call my wife”
Boarders can be a PITA, but ignorant BOs can be a large part of the problem.