The overpriced gas and food, and the limited choices at those toll service centers in Pennylvania and Maryland.
Don’t forget the one halfway through Deleware on 95. Where on busy weekends they deliberately create slowdowns at the toll plaza into MD to create a big backup that extends right to the rest stop’s entrance ramp.
Although I have to admit that PA has a clever setup where they don’t allow direct access between crossing interstates but make cars get off and drive down a mile or two of local streets lined with gas stations and restaurants before getting back on again.