Why do people ignore peronal doubts and truth?

I see so many people that do not question their beliefs and ignore all truth, they lie to themselves just so that they dont have to admit that they are wrong and let go of their false beliefs. They dont realize that nothing bad can come out of questioning beliefs, you will either strengthen your beliefs by confronting these doubts, or you will find truth. But they are terrified of finding truth, they dont see that truth is the most merciless force in the whole universe and whether you choose to ignore it, it will still exist, even if your back is turned towards it.