Blimey!

Him: I'm leaving early. You can too if you want.

Me: Thanks. I'm staying.
Him: Going out in the city later?
Me: Yep. A brit friend of mine just came back from UK, so a bunch of us are getting together for happy hour to say Hello and welcome back.
Him: .......shouldn't it be more like 'ALLO!
Me and several coworkers: ....*hysterical laughter*