We can't see God because we don't want to see God. It is as simple as that.

First of all, God cannot be seen with your eyes. He can only be seen with eyes that show purity, faith, love and dedication. These qualities are brought out by doing good karmas to help ourselves and others.  We can see God if we want to. God can be seen by anybody and everybody who really wants God and is willing to work for it. Everybody knows that if you want something, you have to pay for it. When it comes to God, nobody wants to pay for it. They just expect and demand it to be free. By simply listening, talking, and reading we want to see God. God can not be seen without performing some of the activities required to follow a virtuous life.  Then only can God be seen and understood.

--Swami Radhanandaji