The answer is simple: because he's Rick mother****in' Grimes and he needs a mother****in' beard.

 

I always saw that scene with Michonne as buddies joking around. Rick, though still my hero, was starting to look like a greasy, hot mess. If I remember correctly, she didn't find anything worth while on her run, but she brought back comics, and the clippers... So she gave him clippers, while implying he needed cleaning up.

Anyway, my basic take on the scene is... clippers require electricity to run, so they are pretty useless in the ZA, unless you have a generator, so he just tossed them down.

I never really regarded it as Rick being a dick, but if I wanted to read into it a bit, maybe he threw them with a little tude because he knew he'd never be "Clean-cut, sheriff's deputy Rick" again. Don't know if either is right, but there ya go!

 

I think Michonne giving Rick the clippers was a joke. Why grab something that requires electricity when you have tools that do the job without. I think that scene was meant to show Michonne, not only now thinking of others and doing kind acts for them while out by herself, but also that she's acclimated herself enough to the group to joke around with Rick.

 

Use all that precious power to shave?