Right now, I've picked up a new high-profile client and am having some major challenges with the travelling foh engineer. He's a "veteran", shall we say. He definitely has a good resume covering about 30 years, but so far results have been horrible. Major set-up delays, communication problems with management, horrible show feedback (audible and anecdotal), etc...
I knew it was going to be tough when on show #1, before listening to a note, his first project was to gate
every input at the monitor desk. And what do ya' know? Major problems with kick drum, bass di and acoustic guitar on stage all night.
He walks up to me, looks at my DHA di (of course he didn't recognize it) and says "We're not using that, it's not going to sound good.".

I stay positive and professional & explain to him I've used it on a hundred shows already with nothing but accolades from a myriad of pro engineers. I managed to get him on board with that, thankfully, but it took a lot of patience!
Come to find out he's also been high-passing everything except the bass guitar, including the kick. Drastically. Every time I hit a note, the bleachers rattle! I don't think he's long for the gig, but you can bet I haven't (and wont) invest any of my time & energy trying to coax him into mic'ing a cabinet! lol