Well, there was the trailering saga. First time (for a vet trip) it took 4 people and tranquilizers to load her. Next few were easier, but she was still hard to load, and would still come out soaked with sweat.
Fast forward through about 18 months of rehab and walks, and we're ready to haul out for real rides. She's still not going to get in that trailer, and if she does, is going to turn right around and come out again. (Marvelous exercise for developing quick reactions when you're the one leading her
) But eventually, persuasion & familiarity (and carrots) get her to go in, and we have a lunge line from her halter and around a loop so she can't come back out. A little practice with that, and a few trips out so she discovers that trail rides are actually fun, and she got to the point of nervously loading and waiting while I snapped her halter in. And a year later? Hops right in, stands patiently, never fusses... I think I could just about tell her "Get in the trailer" and she would.