I actually don't use Google Maps -- because it's a crazy mess of buttons and menus that get in my way of trying to navigate. I actually don't use Facebook -- because it's a horrible dog's breakfast of inscrutable icons and I can't figure out its mental model to save my life. And there are many more sites/apps that frustrate me so much that I abandon them for better-designed choices, or even for nothing at all, because at least doing nothing doesn't make me angry.
This function-over-form attitude bugs the hell out of me. People (especially designers) who think that design doesn't really matter as long as the function is okay may not notice the mass of former users who simply throw up their hands and refuse to use their product at all.