My personal pet-peeve is when the obsession with DRY carries over to testing. Testing is not the place for DRY. Reading a test should be like reading a recipe: do A then do B, then do C, then expect result X. When you start abstracting the setup to the nth degree it becomes much harder to understand the test because you have to click around the code to following the abstractions like a trail of bread crumbs, when really what you want is for the stack trace to say "error on line 123" and the cause to easily found near line 123. Tests shouldn't be dry, they should be wet.