Y do some believers give up on God?

I once heard this true story about a Christian whose wife was in a coma for quite sometime, and he was so overcome by depression and impatient about her coming out of it that he took his own life by committing suicide, but shortly after he killed himself, guess what happened next, she woke up. This guy must have been spiritually immature or he must have been doing something wrong w/ his faith. So, y do some people throw in the towel or give up on Jesus under these cirstances?