Stress
You wouldn't think a job this easy would stress you out...and you'd be right. There aren't quotas concerning the amount you take in at the booth, so no worries about whether or not you'll feel the pressure to provide top-notch service.
So long as you show up on time and don't have any complaints filed against you (and who would take the time?), you should be able to carry on whistling to yourself and daydreaming about not being in a tollbooth.
Your best chance of excitement is a "late braker." That's what you call one of those drivers who apparently thinks this is Mad Max up in here, and you don't see them slow down until you make eye contact and it's raining sheets and, oh no, they're about to skid right through the gate—when suddenly the brakes catch just enough and they stop an inch from the barrier. Phew.
Not to worry—a cursory Googling will reveal that there are very low numbers for that sort of thing. Just don't watch the videos from the small amount of times that it does happen. We don't recommend them.