Infectious grooves ?

Chris went in yesterday to do the routine Drug Testing for his new job, and after he was done, he picked me up from work and we went and grabbed lunch. As soon as he started up his car, reggae music came blasting through the stereo.

Him: "Sorry babe, I just felt like listening to reggae now that my drug test is over with."
Me: "What do you mean, 'now that my drug test is over'?"
Him: "Well, I couldn't listen to it before my drug test. This reggae music is potent stuff."