What's too big for a home television

That's it. I'm going to Costco to get the 75". In for the penny, in for the pound. I already have installed a heavy duty ceiling stem mount style t.v hanger. It gives 360 degree swivel, holds anything from 50"-75" and is height adjustable. If I go get it while she is at work and get it swapped out, she's going to have to like it............forgiveness over permission, right?