I agree it's condescending, especially as the clerk obviously wanted to find out why he wants the smallest box to better help him. If your experience from worki

I agree it's condescending, especially as the clerk obviously wanted to find out why he wants the smallest box to better help him. If your experience from working at a computer store is that 50% of the customers ask for thing A but really want thing B because they have little knowledge about computers, it's correct to assume that the customer that wants the machine in the smallest box also has a weird idea of what that means, and probably really needs a different selection criterion. Saying "It's a gift so I don't care about the model but it needs to fit in my carry-on bag" (or whatever the reason) would have explained it, and nobody would have thought the other was stupid. So in this case he's actively inviting that judgement.