The number of d-bags existing in the world that truly believe they will get ahead in the world by brown-nosing is staggering. Don't be so soft or naive.

A loud-mouth in the office has exposed himself. These people are useful in certain situations. Now that you've spotted one in it's natural habitat, note it.

You know management's sensibilities now. Some people can endure a great deal of criticisms and call it part of the job. Some are small and weak; they just can't take the blow to what's remaining of an already 'tiny' ego.

This is a great recipe for making him swallow the company anchor so they can both rest at the bottom...

Become adamant, ask the simple questions, "What, I can't have my own opinion, on my own time?" And let them answer.

If they get angry enough they will say something regrettable; you will then have them by the short-hairs. In a scenario of mutually-assured destruction you can live out your office life in peace. And, should you clown your supervisor like that, the snitch would live a much different life in the office for having initiated such a painful event.

The down side is you could be fired for further insolence :-P

Go in peace, but don't be a victim.