Like most religious experience, which is largely emotion based, it seems that many religious adherents equate grand uplifting emotional responses, such as that of being healed by a medical professional, as a religious experience. At least, it would appear that their response to the emotions they experience is what triggers them to equate those emotional experiences as spiritual–or as related to God. Thus they thank God for healing them instead of their doctor–just to cite one example of this.
It’s what little children do. For example, when my daughter gets help from somebody, but she’s only 2 and 1/2 and doesn’t know the person’s name or who they are who has helped her, and when I ask her who helped her… she makes up an answer and says something like, “It was grandma.”
She’s not intentionally lying–she merely equates the emotional response of being helped by an older person to the same thing she recognizes as the feeling she had when her grandma helped her in the same way at some previous time. Also, she lacks the language skills to articulate the situation and relay the information, it was a stranger that helped me.
When she matures, mentally and emotionally, she’ll be able to recognize the person who helps her and thank them directly.
In a way, I perceive the thankfulness toward God not as an obligatory form of veneration but rather a stunted social understanding of one’s emotional responses with a limited ability to express one’s gratitude and respect to those who have helped them. Like my daughter, they simply attribute the emotional response they feel to a figure head–in this case God–rather than to the actual person responsible for triggering that emotional reaction by doing something such as helping them.
It also explains that when called on their giving thanks to the wrong person they, usually, take offense that anyone would have the audacity to point out their mistake. Why? Because in their mind it’s not a mistake. Just like in my daughter’s 2 year old mind it’s not a fib. It’s simply what she feels. While it may not diminish her feelings, which are genuine, it doesn’t make her attribution correct either. My daughter is wrong to suppose help always comes from Grandma just as religious people are wrong to assume help always comes from God.
Sometimes, we simply have to learn how to thank those who help us for helping us–God has nothing to do with it. Becoming an atheist has taught me to be grateful for others in a way I took for granted when I was religious.