[reaperducer]

And when they're already all sold?

Or when, like happened to me, you get involuntarily relocated from the exit row seat you paid extra for? (Without compensation, since it was done by the flight crew during boarding and not in advance. Thanks, Singapore Airlines!)

[toomuchtodo]

Sometimes it's unavoidable. In your anecdote's scenario, I would perform a credit card chargeback.

[EliRivers]

You're lucky they didn't drag you out of your seat and have some off-duty moonlighting local police thugs beat you senseless :)