I bought my Scamp specifically to learn how to work on older cars and to gain an understanding of how engines work. While not a pet peeve of mine, I still don't understand why folks with the skills and are physically able, do not do the work on their own cars.
Again, not really a pet peeve, per se, but get that car out and drive it! It wants to feel the fresh air. It wants to have people admire it in the grocery store parking lot. Heck, the owner deserves it after putting in all that time and effort.