I once ran out of cash to buy a train ticket and saved the day by managing to get an impromptu loan from a Good Samaritan stranger fellow passenger. More at Ketharaman Swaminathan’s answer to Ideally, how many credit cards should I own?.

That was the day I realized that a credit card is a right source of money for consumption.

That was 35 years ago.

Since then, nothing has made me realize that a credit card is a wrong source of money for consumption.

During this period, I have not paid a penny in interest or financing charges. I always pay my balance in full every month. (Okay, there was one exception to this, but was the best use I’ve ever put my credit card to, so it doesn’t matter.)