I've done about the same number of shows on both sides of the fence, and I have to say I've run into remarkably few problems with whoever was on the other "side". As a FOH Engineer, I always make sure I've got my stuff setup and the board programmed, and mics out and wired up - before anyone in the band walks in. When they get there, the first thing I do is talk to them face to face, shake their hand(s), talk a bit about what's up in the venue, whatever. The point is I try to start the relationship as teammates, not adversaries.
As a musician, I follow similar principles - I talk with them before setting up any gear. If it's someone I haven't worked with before, I'll explain that I have a pedalboard, and will try to send FOH a signal that's good for use in the House as is, but if they need to change stuff to make the music works, that's their job - that approach seems to get me more of my sound much better than demanding they not touch my sound. Again, I find that most FOH folks want to do a good job, and if they're competent, starting as teammates makes the gig much better for everyone. If they're incompetent, I learned long ago that I can't run FOH from the stage, and no amount of complaining will fix anything - it's always best to be nice, no matter what you run into. Even in the event that the gig turns into a musical dumpster fire, if people notice that you're doing your job as well as you can, not complaining, and are part of why it wasn't even worse, that kind of thing helps your reputation. Having a reputation of being easy to work with is a big part of getting the gigs you want, no matter if you're a musician or a tech person.
