Funny experience with CBP at MIA.
Came back from a mission trip in Port-Au-Prince. Luggage was unloaded downstairs and customs was upstairs. My buddy and I carried up about 10 trunks (for the group of us) on a very warm day in a very warm airport.

We got to customs and we suddenly got the fifty question routine culminating in "Why are you two sweating? You got something to hide?" To which my buddy responded: "There's no snow here, it's hot, and we just carried 10 large trunks up two flights of stairs. And we don't sweat, like you, we perspire." The agent was not amused.