I'm planning a passenger charter in the airplane with the irritating weight and balance. It can't be flown single pilot with full fuel, so when a charter involves something like flying to A to get people, dropping some off in B, picking more up in C, and taking them all back to A, you have to plan ahead carefully to make sure each leg will work for the number of people and the seats you have put in the plane.
Every fleet seems to have one of these: an airplane that is the same type as the others but through some quirk of history and equipment is way out of balance. I wonder if this continues to widebodies and there's some United captain today looking at his loadsheet and saying to his FO, "Great. We've got N124SA today." Does Air Canada have one B767 that dispatchers and loadmasters despise, and long to see get a shiny new paint job and be towed by the new girl on the ramp crew or left outside in a hurricane? (It's always the shiniest airplane in the fleet, or the one featured in advertising, which gets destroyed in a freak accident).
I work out the permutations and then that airplane is grounded for some mysterious engine problem unrelated to the weight and balance.