Why does buying a used car suck so bad?

We have been in the market for a used car for a couple of weeks . Here are our experiences in Ottawa so far :

Dealership 1 - Made an appointment to see one car and when we arrived they showed us a totally different one and told us that the one we wanted just sold. They are continuing to pressure us to buy the model they have on site even though it isn’t what we are looking for.

Dealership 2- Paid a refundable deposit for a car and they called back that evening and said they sold it to someone else. Lovely.

Dealership 3 - Refuses to give us the interest rate up front until we agree to purchase the car. Do people actually agree to this ?

And none of these are Dilawri!