I should add that I now understand 'lack of confidence' is itself an excuse for not taking action.

Waiting to be confident before taking action never works, I know that from my own experience. You need to take the actions first to gain experience, improve, then the confidence comes after that. But it involves taking some risks.

The first obstacle is actually fear. Fear of failure, embarrassment, rejection (AA is a perfect example). And the more you avoid facing up to it the larger an obstacle it becomes.

It starts to dictate how you behave, which leads to your comfort zone shrinking instead of expanding.