Misunderstandings

I was buying a chair at OfficeMax tonight, which I had them assemble since it was free. The conversation at the counter:

Me: Hi, I’d like to pick up a chair.
OM: Sure, what’s your name?
Me: Matt
OM: OK, one moment.
(gets chair)
OM: Alright, would you like a chair mat?

I then stood frozen for a moment, since I misunderstood this as “would you like a chair, Matt?”. Was he going to make me plead for it or something? Why would he play games like this? I said “excuse me” (the “I didn’t hear you” kind, not the “how dare you” kind) and had him repeat himself to stall for time, and luckily I figured it out after that. Otherwise I would have been stuck.