Burt (Mark Boone Junior)
Character Analysis
Burt doesn't play a huge role in the film, but he does let us see how Leonard interacts with people and how people usually interact with—and more importantly, manipulate—Leonard.
Burt seems to be simultaneously deceptive and sincere. In the first meeting between Leonard and Burt that we see, Leonard explains his condition to Burt (and also to us, the viewers) until Burt just can't hold his smile any longer, giving away that he has heard Leonard say this all before. While it may seem like Burt's just taking advantage of Leonard for a good laugh, he continues the conversation by showing what seems to be sincere sympathy for Leonard, saying that it "must suck" and that it's "all backwards."
But apparently this sympathy doesn't go so far as to affect him morally. Business is slow and when his boss orders him to rent Leonard out two rooms, he doesn't seem to have any qualms about it. However, when he gets caught, he's nice enough to be honest with Leonard, telling about the two rooms and reminding him to always get a receipt (advice which Leonard thinks is good enough to write down… although to be fair he writes everything down).
So what's the point about Burt? He's kind of like us; just a normal person that takes in Leonard's condition like we do. He's a little sympathetic—but he's always looking out for number one. And while we may think that's selfish, compared to our other characters he seems like Mother Teresa.