The weird thing about working at your peak is that it doesn’t occur when you know everything. If you want to do your best work, you have to be learning something new. There is a reason for this; you are engaging a different part of your brain. This is why the new people to the organisation are so valuable.
Many would say that low self-esteem is bad, but there are situations were low self-esteem is powerful. It is when it is coupled with another invaluable attribute - Drive.