Partial convert !
I was using the Aera at the time, did not realise that the default airspace warning did not include class A, and climbed a few hundred feet into a fiddly spur of airway doing local flying from a semi-familiar airfield. I picked it up doing a routine cross check against the chart, dived out of it, then grovelled and revisited my understanding of the kit.
I learned about flying, GPSs and good airmanship from that...
G