The new Gmail toolbar (top) versus the old Gmail toolbar (bottom):
Maybe it's just me,* but sometimes words are just plain better than icons. I think this is particularly so in an application that has keyboard shortcuts: the words serve as a mnemonic. And note also how the old toolbar takes up less space, despite having two more buttons.
I'm betting that had I not put the old toolbar under the new one, it would have taken you considerably longer to puzzle out what the buttons in the top one do.