Don't be. You feel that way because you think the total amount of BTC which is paid for pizza with today's value of BTC. If you think differently where the price of BTC that day is different to this day. That time 10k BTC is worth around $40 compared to this day's BTC price so that's why the buyer didn't feel bad or disappointed. So, today if someone wants to buy pizza and they accept BTC then you won't have to pay 10k BTC just to buy pizza but rather pay BTC that is worth the pizza let's say $40 and that would be 0.0013 BTC.