The biggest barrier to positive change is identity conflict.

The more deeply a thought or action is tied to your identity, the more difficult it is to change it…… The biggest barrier to positive change at any level—individual, team, society—is identity conflict. Good habits can make rational sense, but if they conflict with your identity, you will fail to put them into action….

Over the long run, however, the real reason you fail to stick with habits is that your self-image gets in the way. This is why you can’t get too attached to one version of your identity. Progress requires unlearning. Becoming the best version of yourself requires you to continuously edit your beliefs, and to upgrade and expand your identity.

James Clear from Atomic Habits