I tell you, doubts usually come to you when you choose the right thing.
Doubt is always about something positive. Have you noticed this? We always doubt the honesty of a person; we never doubt the dishonesty of a person.
We ask our dear one, ‘Do you really love me?’
If someone tells you, ‘I love you’, you say, ‘Really?’
But if someone says, 'I am angry at you', you never say, ‘Really?’
Similarly, we always doubt our capabilities but we never doubt our incapability.
When someone asks you if you are happy, you say, ‘Well, I am not sure.' But you have never said the same when you are depressed. You are so sure of your depression.
You are so sure of negativeness, but you always question the positive things in life.
So doubt also indicates that there must be something good.