"Everyone regrets spending their bitcoins."
This is honestly the most stupid reason not to spend your coins. There is no difference between spending fiat that could've been used to buy bitcoin and spending bitcoin itself ECXEPT the exchange fees.
Those fees are the only good reason not to spend bitcoin. "It is not financially optimal for me to spend 100$ + 1$ in bitcoin when I can simply pay 100$ in $".
This is the only valid reason not to dpend bitcoin and it is 1000% valid. Spending and replacing is not free.