A) They warp in the middle. Sometimes this causes the drawers to catch on the frame while opening or shutting.

B) They have a little ridge around the boarder on the top that is about 1/8 inch or 1/4 inch. This makes it hard to put something like a glass/drink, as it sits crooked and unstable if you set one on that ridge area. Along with the warping in the middle, it makes it virtually impossible to put anything liquid on top as this causes unsteadiness (easier to tip over and spill). Notice how the liquid in the cup is not level. However the ridge would contain the spill from running over if that is what its purpose is.

C) It would be nice to have a way that they could lock into each other to be able to stack them.

D) The way they are built, the frame is exposed and that collects a lot of dust along the sides.