Probably preaching to the choir here, but:
About 10 years ago my best friend called me up. He’d graduated from an expensive private school with ~$100k in student loan debt, and had been admitted to law school at the same place. Turned out he was having a wee bit of trouble financing it. He wanted to know if I’d co-sign on a law school loan or two.
At the time, I didn’t even know what that meant (I got through college with no debt, thank the Old Gods). Called up my dad who strenuously advised me to under NO circumstances co-sign on anyone else’s loan, ever. So I told my buddy sorry, but no.
Unfortunately, our friendship was never the same after that. I’m sure he resented me for not being a true bud and signing. But somehow or other he managed to get financing for God knows how many more tens of thousands in loans for law school.
Fast forward 10 years. Found out recently that, like many with law degrees in the current economy, his income hasn’t kept pace with his loans, and he’s defaulted on his student loans and the debt collectors are pounding on his door, taking his car, garnishing wages, taking out liens, etc.
And if I had agreed to co-sign those years ago, those debt collectors would be coming after me.