Normally, praising is a good thing. However, I found that if I praise a person while they are repairing the floor, it tends to lock them into that task. Unfortunately, I don't see the task progressing, they are just going through the motions (task is actually frozen, though the animation continues--? game glitch). In this case, I just remove them from the task and then put them back at it. Now I just don't praise them while they are doing the floors. I just keep putting them back when they wander away, as with other jobs, until they finish. It really only takes a couple minutes to finish a floor repair.