I get frustrated trying to judge whether acne creams are having any effect. In the spirit of a controlled trial, I used one on just half my face for a few weeks.
[[A graph shows pimples vs. time, with two lines--one remains one steady, and one is declining.]]

It was cool seeing the effects so clearly, so I got some friends to try different treatments in an impromptu study.
[[The narrator looks in a mirror, sees a half-pimpled face, and applies a treatment.]]

[[The narrator is talking to a blonde and brunette friend, each with some pimples also.]]
Narrator: Okay, you try the saucylic acid first.
Blonde: Wait, we should randomize the trials. Got a coin?

Narrator: Okay, call it. Heads, she gets the--
(Off-panel): YOU!

[[Batman runs into frame and punches the narrator. The coin goes flying.]]

{{Title text: Why do all my attempts at science end with me being punched by Batman?  (P.S. benzoyl peroxide soap works great.)}}