I have both showed up to the wrong airport as well as on the wrong day (or conversely having booked the wrong day without noticing it) and I found that a healthy dose of self-deprecation in those moments is the only path to a positive resolution. Same goes for the handful of times in my life I have woken up in a hotel room several hours past my ETD.
^
This is right up there with "HUACA" on the list of best FT advice ever.
I'm thinking of the time I left my rollaboard in the overhead on HKG-SFO, didn't realize until I was already at baggage claim. Pleaded mercy, they called the gate, and one of the FAs brought it through immigration for me.