Cathode Ray Tubes probably wouldn't work very well if they sucked electrons away from the screen instead of launching them towards it. At a deeper level it doe

Cathode Ray Tubes probably wouldn't work very well if they sucked electrons away from the screen instead of launching them towards it. At a deeper level it does start to matter when you get down to the physical level of transistors because electrons and holes (places in a crystal lattice where an electron could go but isn't there) move differently. P-type transistors generally can't be made as conductive as N-type transistors because, with plenty of handwaving, negative charge due excess electrons move easier than positive charge due to a lack of electrons.