Because it pains you to see a fellow human being missing out on such an awesome pleasure. So when you're filled with enthusiasm about being close to God, you want all of humanity to have that relationship as well. This is not like human beings who become jealous when the attention of their beloved is directed elsewhere. When it comes to God, there's no jealousy when you see other people having a relationship with Him. Because God is infinite.
Every human being has a longing for the transcendental.
Take pleasure in the infinite beauty, grace, power, wisdom and meaning of our Creator. People shy away from God because they're afraid it will stifle them. Yet they'll climb mountains for the ultimate transcendental pleasure. Artists think they have it, but there is more. God is the real aesthetic experience.