We got a laptop at work. It's an Acer gaming thing which we bought becuase it was the cheapest thing we could find with a GPU in it. It also has an RGB keyboard (which is terrible, half the keys stick). The default setting is to flash a key when you press it, which then fades out over a second or two.

See the problem? Whenever you typed a password, you would see all the letters you typed lit up on the keyboard conveniently in brightness order...