My mom's stovetop. It is flat and white; any time the stove is used, any residue on the bottom of a pot or pan creates a horrible stain that must be scrubbed. Even an apparently clean bottom will create a stain.
A rechargeable computer mouse. The cable for recharging goes into the bottom of the mouse; therefore the mouse cannot be used while recharging.
My computer informs me my disk is full, but there is not a window to open that tells me how much of my disk is full, or where the stuff is that is taking all that room. After a morning of deleting stuff, I don't know how much progress I've made. I delete some more stuff, and now I have less room than before, 4.9 gigabytes instead of 6.