My musical tic is in season

Other drivers must think I have a tic. They see me at the wheel of my car and my head is jerking from side-to-side, rhythmically.
That latter adverb offers the clue that my "tic" is merely a seasonal affliction: It's listen to REGGAE in the car season again.
Warm weather and a new, larger iPod have combined to shunt my current musical tastes in a single direction -- the direction that points to JAMAICA.
"Choo choo wakka choo choo wakka! Choo choo wakka choo choo wakka!"
"ROCK STEADY TRAIN," a 1967 gem by EWAN & JERRY just blasted out of my car stereo and now it's replaying it's catchy self in my head.
Ewan McDermott and Nathaniel "Jerry" Matthias are a couple of my favorite reggae performers, their songs so catchy that I occasionally find myself exhibiting another "tic" while driving: My shoulders shake in time to the music, too.