I always love reading what people say about the motor trade when they obviously know nothing about it!
If you want to know just a little bit of truth.
general dealer markup is 20%.
there will always be more margin in a vehicle the dealer bought at trade rather than a customers trade in. If you can establish which it is you will have a greater ability to bargain with the dealer.
they are not trying to pull your pants down, they are making a living, if they were actually robbing everyone blind they would be retired by now.
Dealers pay 20% VAT on the profit they make. Most people dont ever think about this and slate the dealer for trying to make a fortune.
CAP and glasses are trade guides, they are prices often based on what a car would make at auction or a sale to the trade (especially CAP). Dont assume the value you might get shown is what your car is worth, its worth what the dealer is willing to pay.
Dealers do also get it wrong, more often than you might think and can loose thousands on a bad deal.
last but not least, if you think a dealers job is easy then give it a try yourself and see how many sleepless nights you suddenly have...