One of my most pettest peeves is people who don't do a job right; they half do it or don't use the correct materials/methods (or don't bother to learn what the correct materials/methods are). My dad always called this "doing a half-a$$ job."
Yesterday, DH and I spent a few hours out at the new house starting on cleaning the kitchen. We filled two trash cans full of "tenant residue" and then I started scrubbing the cabinets clean in preparation for putting down shelf paper. The cabinets are site-built and the insides are all nicely painted with oil-based enamel paint (which is what you should always paint kitchen cabinets with). At some point, some paint moron decided to paint the outside of the doors and they used flat latex wall paint. Moron.
Flat wall paint on cabinets picks up dirt very easily. Latex paint painted over oil-based paint without a primer will come off if you try to clean off the dirt. Notice the lovely circle of grunge around all the cabinet knobs prior to my scrubbing. Also notice the nice window with no sink beneath it, but that's another story and the same moron.