Have you ever charged interest on a personal loan, or has anyone charged you interest on a personal loan made to you?

I was only charged interest on a bank loan or my car loan.

I never charged interest on money I lent but a couple of times I paid interest on loans from the loan shark people: borrow $40 and pay back $80.

What an interesting question. No.

Yes, I have charged interest on a loan.

Back in the "good 'ol days" when I had money (sigh), I loaned my sister money so she could buy a house.  I wouldn't have charged her interest, but due to the amount, her husband insisted.

I have not because I don't lend money.  My husband did it all the time when he would sell rental houses to individuals.  Most of them would never have qualified for a loan and had lived in the houses for years and years as tenants.  These low income hard working people would beam like the stars when they realized they could own their own homes.