Why do different religions experience the SAME spiritual experience?

Ok, so I grew up Christian and my love for Jesus Christ led me to learn more about how my religion is the "right one". However, I got a little confused because as I started to conduct my own research about other religions and history of religions etc. I realized that all religions carried a similar formula mathematically. Although the belief & God are different the end result is similar. They all almost mirror each other. How can two different religions experience a "spiritual experience" if there is only "one" God. I've personally never had one even though I was deep into the church and prayer etc. Sometimes I wonder if it's just a state of mind and delusions/illusions of the mind. It's like when someone drinks juice & they were fooled to believe there is alcohol in there and they think they are drunk until you tell them there really was no alcohol in there. Almost every person that claims a near-to-death experience sees whomever their God is so if there is only one God why does everyone see their God? Is it just an illusion as you're losing consciousness? There is no way to disprove or credit what is going on inside a person's mind and what they are saying. Anyone can fake anything and there is no way to prove it; likewise, someone can have a true experience and there is no way to prove it. Can it be just an illusion? I'm not judging or looking to offend anyone I'm just really disappointed.