The fed interest rate is the foundation for pretty much all loans, cars, mortgages, whatever.
Low interest rates are good for borrowers. I want a car, or a house, or a power plant, or a jet, or whatever. I want to spend some money that i don't actually have. This changes the economy because more money is moving around.
High interest rates are good for lenders. I've got this pile of cash that isn't doing anything. The higher the rate, the more likely i am to loan it to someone who wants to do something with it.
The higher the rate, the more sure the borrower needs to be that they can actually put that money to good use. Not only do i have to get you your money back, i have to get you all the interest as well. Lower rates mean more activity, more people borrowing and buying stuff. Higher rates slow things down, but bring more investors out.
Say the fed rate went up 5%. Yesterday i could give you a home loan for 5%, today i could give you a loan and make 10% instead. Since that rate is the foundation of everything, my risk stays the same, but it's much tougher for you, because you have to come up with a bunch more money. They made a tiny, probably imperceptible change to you and I, unless you're actively looking to take out a loan.
Anyway, that's the gist. Borowers need to be a tiny bit more sure they can pay the interest.