Frankfurt to Bangkok, 11 hours, seat 41E. Middle seat, next to the toilets, a toddler kicking from behind. I didn't sleep.
Getting off, I ended up walking next to the man from 2A. He looked like he'd been to a spa. I asked him, half joking, what a seat like his costs.
"1,790 euros. Return."
My economy ticket was 1,140. The airline's own site wanted 4,500 for his seat on the same flight. He had no status, no stack of credit cards, no points. He'd simply started his ticket in Rome.
That's when I learned that every business class seat has five prices, and almost everyone only ever sees the highest one. I spent the next two years mapping all five on every major route. That map is your card. I haven't sat in 41E since.