Donation was more than anything an attempt to get the characters of Mouse and Bear into more typical “human” interactions. The last two strips using the characters were much more “talking head”like and I know that even here they’re technically talking heads, but there’s more action and setting that implies “otherness”.
I used to be a cashier for a huge supermarket chain, and it sucked the life out of me, every day. Any sort of retail will do that to you, really. The worst part about any of these retail gigs is the long list of questions you’re required to ask the customer. If you don’t ask each and every one, you’re likely to get written up. It’s terrible. I’ve been on the other side of it as a consumer, too, and most people want nothing to do with all that jazz. They just want to pay for their items and get the hell out of there. If I wasn’t required to talk to the customer, I don’t think anybody would mind. Everyone hates meaningless smalltalk.