We were doing an annual on a Bellanca Turbo Viking a couple of years ago. It was obvious once we had started, the aircraft hadn't received a good annual for quite a few years. The thing had lots of issues.
One of the more interesting things we found was that the elevator didn't seem to be getting full up deflection. After looking around for a while we found the problem. Tape had been applied as a gap seal (poor mans speed mod) between the horizontal stab. and the elevator, restricting the movement. Tape residue was noted on the top side of the stab. and elevator, the tape had been removed, tape was still on the underside however. Once this was removed as well, full deflection was restored.
Like I said the aircraft had many issues due to years of poor annuals. After we were done rectifying all of those issues, the owner was left with a sizable bill. He hasn't brought the aircraft back since.
Another example of an aircraft with a history of of shoddy annuals (if that even) is a Cherokee we had in about nine months ago.
I tried to avoid working on it because I knew it was a piece when I towed it down from the other end of the airport. I did however get stuck doing the brakes and wheel bearings.
I knew that the guy didn't want to spend much money so I felt bad when I pulled off one wheel and and found the brakes were shot, as well as the bearing and race. I swear the bearing had more dirt and rust than grease. I already knew the thing needed new tires all around. I also noticed that the wheel itself was looking rather corroded.
Around this time the owner stopped by. I showed him the brakes and wheel bearing and informed him they would need to be replaced. The shocking part was when he told me that he wasn't surprised as they hadn't been changed in the 10 years he had been flying it.
After hearing this and then having an IA confirm the wheel was shot I said F- it, especially when I found the other side was just as bad. He bought all new main wheels, tires, bearings and brakes. We did try to find cheaper used wheels, but couldn't within his time constraints.
Once again, the owner wasn't too happy with the bill for correcting all of the issues (a large part being those new wheels) but honestly I didn't feel bad at all anymore. In my opinion he shouldn't have been allowed to own or fly any airplane.
Oh yeah. We also found some dents protruding from the aft fuselage. When we looked into the cause of them, we found that the ELT had no mounting bracket and had been flopping around back there for some time, causing the outward dents. IIRC the ELT was found in the off position.