That was obvious enough

I've owned this house for 6 years. Weeks into owning it the stopper on the bathtub broke. It was one of those stoppers that is built into the tub and the little lever thing was broken before I moved in. For all these years the drain has not been very effective, so that each shower involved standing in a couple inches of water.

I've never known what was wrong. Today I cleaned hair out of the drain, just like I have plenty of other times. This time though my finger slipped a bit and hit this thing inside the drain that opened it up. That's right, the reason for the water accumulating was the drain was partly closed. All it took was pushing the little thing away.

Six years.