Updated April 13th, 2020.
Mail is even better when you customize the toolbar to be just the way you like it.. This video tutorial– less than two minutes long– will show you how it’s done.
Click the picture below to start the show.
UPDATE: I should have mentioned that you can customize the main Mail viewer window’s toolbar AND the individual Mail message window’s toolbar– changes in one do not affect the other. So, customize Mail’s main viewer window’s toolbar, then double-click a message to open up a message window and modify that toolbar also. If you want.