"It's only because she likes you so much." Mike assured Harvey with a laugh of his own. That and Donna seemed to be the only person around the office who wasn't afraid of Harvey at least a little bit (aside from Jessica of course), otherwise Mike was sure she'd never even attempt half of what she did.
Mike quirked an eyebrow at Harvey when he suggested that they were supposed to celebrate something. Mike wasn't sure what exactly they were supposed to be celebrating though, all he could think was that Harvey was up to something. Because he was the one that gave high fives and tried to coerce Harvey into fist bumps and generally made a fool of himself when it was the time to celebrate.
But Harvey suggesting it? Well Mike was pretty sure he'd missed a step somewhere. "Chest bump?" He suggested, knowing that would be turned down faster than any other thing he'd tried to talk Harvey into before.