Doors and trapdoors lag.

In singleplayer, when opening a door or trapdoor, or anything red-stone related it takes up to from 5-15 seconds to appear visually.

This is different from "Block lag" because breaking/placing blocks is shown just fine. This also does not affect chests.

I think this might be related to using Java 1.7, however lots and lots of people use Java 1.7, since it is hard to update it on mac/linux sometimes.