Life is a balance.
Being thoughtful, cogent, and evaluative of your own emotions, actions, and intentions can be helpful & introspective, but to an extent.
Some also need to learn to trust themselves and not over-analyze their every thought, emotion, and behavior. They need to get out of their own head and trust in what they're doing, saying, or feeling—instead of constantly second guessing and critiquing themselves.
For "if you double check everything, you'll get half the amount of things done in life."