You know, I'm quickly reaching a point where I want the default browser to work in Incognito mode, and the browser should only switch to regular mode when I explicitly whitelist the domain.
https://support.mozilla.org/en-US/kb/open-new-tab-firefox-fo...
The only thing it doesn't have is a way to auto delete cookies without restarting (which expires session cookies, which is a native option).
That's how I use it, cookies default to session only and a few sites get saved across sessions.
Another easy tip is to separate out anything that requires persistent login (ex: gmail) to a separate dedicated browser.
Browsers need to be seriously redesigned with privacy (aka security) in mind. The javascript execution environment needs to be gutted to remove security leaks like screen/window size. And incompetently (/maliciously) designed APIs like websockets need to be thrown right out.