If you were ever into the position of styling an input type text in making it bigger with the text centered vertically in the input you'll notice that's a major pain in the butt to do it.

Firefox doesn't respect line-height and IE8 has a very strange bug that i'll explain below.

Take the following code:

Untitled Document

You'll notice that for some strange mambo-jumbo reason the text doesn't actually get pushed down by the padding.