My son is spoiled but I want him to enjoy life

We got the kids a blow up water slide. It is pretty awesome. Brendan doesn't usually like 'toys'. He never says he wants anything. He never has a favorite toy that he just has to have so when he does like something I get it. Everytime we showed him a water slide in the store he lit up and asked us to buy it. So we did. I looked at a ton of them and found a great one at BJ's. It has a smaller slide which is great for Makay and Brendan when we don't have th energy to lift him onto the bigger slide. The sides are nice and high so he can't fall off while zooming down all on his own.
On the way home from therapy last night (which he did awesome at) I told him that Derek had set it up and he can try it when he gets home. He told me no he didn't want to go on it, he wanted to watch cars on Youtube. Well as soon as he saw it outside he said "mom can you get me changed?" He wanted in and he LOVED it. We just need some warmer weather so we can actually use it