Yeah.

So bonds are loans, right? War bonds are money you loan the government so they can beat the Germans and they'll pay you back. Savings bonds are money you loan the government so they can do whatever and they'll pay you back. A municipal bond is money loaned to some city or whoever and they'll pay it back. Really, the difference is a loan is between a bank and a customer while a bond is between an organization and anybody who is qualified to buy the bond.

So if I need a car loan, I go to a bank. They look at my credit history, decide how risky I am and offer me terms. I can shop for other banks, who might give me other terms. No matter what, the bank is out the money if i don't pay. They can recoup the car but they're not going to get full price.

But if I need a car company I also go to a bank. They talk to their friends, grease the wheels, put together terms, arrange for me to meet with investors and basically put together a deal whereby I get a bond (big pile of money) that investors buy. No matter what, the bank makes money off the top. They lose nothing. All they're doing is skimming off the top. All the risk is with the people buying the bonds. I could be Henry Ford, I could be John DeLorean, I could be Liz Carmichael. The bank makes money, and really faces no legal consequences for "oopsie! introduced you to a scam artist! Too bad, so sad!"

As you might imagine, the bank that has your savings account and offers you mortgages operates under very different principles than the bank that writes AT1 convertibles. You've got George Bailey and his savings and loan on the one hand; on the other you've literally got Goldman Sachs. One pools its customers' money and uses it to facilitate the financial transactions of its customers. The other buys bonds, sling moneys around and otherwise attempts to multiply it through fornication.

So as the country was picking up the pieces of the Great Depression, one of the fingers pointed was that banks were taking everyone's money and playing the ponies with it. They weren't protecting the savings of their clients, they were buying stocks on margin - in other words, using clients' money for risks the clients didn't authorize. Which is one thing if you're an investor at an investment bank. Quite another if you're a customer at a thrift. So Congress said no more and made it so that if you protect people's money for a living, you can't use it to play the ponies.

Graham Leach Blihley blew that shit the fuck and gone out of the water. More than that, the FDIC had been watching over thrifts and the SEC had been watching over investment banks. But thrifts that decided to play the ponies weren't under the purvey of the SEC and the FDIC has no mechanism to determine wither thrifts were playing the ponies in a safe and legal fashion.

So while you might think that taking everyone's mortgages, rolling them up into bonds and paying the biggest yields on the ones most likely to fail is counterintuitive and stupid and fuckin' hell nobody should do that, there was no sanctioning body whose job it was to say "hey Washington Mutual stop writing mortgages you expect to fail so that you can get higher yields on the bonds you roll them up in."

TL;DR: Glass Steagall separated banks that serve consumers and banks that facilitate investment and regulated them separately. Repealing it gave banks a lot of leeway with customers' money and made no provisions for regulating their behavior. Everything went as expected.