the diagnosis thing Im with everyone else that said the only way to tell them apart is with special tests.

The toaster thing, I have one of those and if I am toasting only one slice and dont put it into the slot with the arrow it wont work. I thought it was just me so I read the toaster manual and that too said for one slice use the slot with the arrow otherwise the toaster wont work, with mine
I push the handle down and the bread just keeps popping back up again with this grinding noise. I then called the company that made the toaster (GE) and they told me they make their toasters that way so that if kids are making the toast they wont get burned by putting their fingers in the side with no toast. only the side with the arrow will light up when making one toast. I thought this was a great idea for keeping little kids just learning how to cook their own toast safe.