I thought the beatdown was warrented, but the timing was off. He needed to do that last week to Smack the Smirk off Sam's face. Or even when Sam first showed up and admitted with just a shrug that he'd beed topside for a year and was just now getting around to telling Dean.

This? Right when Sam admitted everything and that he needed help? It felt out of place. And yet... well it's understandable. Poor Dean had a lot of pent up rage.

I'm not as worried about the Lisa thing. I think they just need a break. I'm betting one way or another he winds up back in her arms in the end.