Here I am going to say something which may come as a bit of a shock. God doesn't necessarily want us to be happy. He wants us to be lovable. Worthy of love. Able to be loved by Him. We don't start off being all that lovable, if we're honest. What makes people hard to love? Isn't it what is commonly called selfishness? Selfish people are hard to love because so little love comes out of them.
God creates us free, free to be selfish, but He adds a mechanism that will penetrate our selfishness and wake us up to the presence of others in this world, and that mechanism is called suffering.