Do you feel a strange sense of obligation, even if it's not necessary or even harmful,?

No! It infuriates my MIL, who insists that we are there when the gate opens and stay for the fireworks as the gates close. They have season passes, but my kids and I do not. I take them once a year, and my in laws insist that I get my money's worth. I don't see the point in being at Cedar Point at all if we're not having fun.