The sequence of Money Supply - Interest Rate Until now I've learned that the Fed controls the interest rates and that affects the money supply. For instance,

The Fed increases Interest Rate ----> makes firms/households reluctant to borrow and Banks loan less ---> less money supply.   

However, what is the economic intuition for the opposite sequence? So 

"Fed increase money supply ----> interest rate decrease"
"Fed decrease money supply ----> interest rate increase"

I have never thought of this sequence - I have always thought of the interest rate as the causal factor and the money supply change as the result. I would appreciate it if somebody could explain how the opposite sequence is also possible. So to put it simply,

if Fed increases/decreases the money supply, why does interest rate decrease/increase? not in economic theory, but in real-life explanation please.
It’s just supply and demand. The interest rate is the price at which you can borrow money. For a fixed demand curve, if there’s less money available (the supply curve shifts left), the market will clear at a higher price (higher interest rate). Similarly, if there’s more money available for lending, the equilibrium interest rate will be lower.