How to tell dad i dont like the desk he bought me?

im 13 if that makes a difference. he bought the desk on craigslist.i dont mind if its new or not. but he bought me this giant desk that takes up alot of space in my room. and i HATE it. i dont know how much it was for but i still hate it. we have two other desks that we dont use in the house so we dont need to get a new one. im just having a hard time telling him i want to trade with another desk in the house. i mean he spent an hour and a half getting it ready and he was so happy seeing me pretend to be happy. what should i do?