I was anxious to ride last summer and hadn't had a motorycle before, so I paid a shop to do some work for the sake of time.
Over the winter, while I was giving the bike an overhaul myself, I noticed all the little things they #$%*ed up. The new airbox they had gotten and installed for me was in upside down, and missing some parts, and one of the mounting screws ended up going right into the plastic so I couldn't remove just the filter. Carb drain hoses not hooked back up. Fuel lines routed messily and kinked up. Etc.
Now that I'm more familiar with my bike, I won't let anyone else touch it. I second the idea that, if paying someone else, that you at least should give it a good inspection afterwards to make sure things were done, and done correctly.