complex schedules to maximize fleet and crew efficiency. Those efficiencies are part of the reason why so many of us can afford to air travel, which is no longer a luxury item.

Those efficiencies also minimize idle time, so when something goes wrong somewhere, the system has only so much tolerance before the effects cascade down.

That plus government regulations (the not-so-bad kind) that ensure the crew taking you places isn't running on fumes.

IRROPS are part of life, no need to get too upset about it. Just relax and be kind to the crew. They deal with enough crap already.