That's certainly fair. I'm in London 2 or 3 times a year and usually try to hit something new if I have personal time. But I don't need to hit the British Museum on a given trip. London's probably something of an extreme because there are so many must-dos. But I think it's also fair to agree with the general sentiment that traveling shouldn't be exclusively about a check list. (If it's Tuesday it must be Belgium.)

Of course, it you're spending a little time in a place for what might be the only time there are probably one or two things you sorta have to see. But you should mostly avoid (IMO) just checking off sites.