Learning about the financial system really changed my perspective on how to deal with money in the long term. It has had immediate effects on my life.
I learned about taxation in detail, opened an account on a discount brokerage, changed saving patterns, and have made a portfolio for the next 10 years.
I have a spreadsheet of how much I can spend and componentize my bank cards. One is for bills, another for spending, and the rest are investing accounts. When I get a paycheque, I put how much I need for bills directly into the bill account, the allocated amount for investing in investment accounts, and the rest in my spending account. I know exactly how much I can spend at restaurants and I don't need to do any mental math.
I really feel like learning this at age 22 was life changing and I will be thanking my self in the future.
"Invest early and often" - Jack Bogle