Harassed by Homeless at Drive Throughs

I get off of work late sometimes and just want to get a bite to eat. It's getting so tiring dealing with this every night. When I tell them no or ignore them they get visibly upset. Last night as I was leaving McDonald's the man I denied starting pushing a large rock at the end of the drive through lane. Luckily I pulled off just before he was able to push it off the curb.