It could sound trivial, but a simple note feature can become such a powerful tool to combat hindsight bias. The Notes feature allows you attach a note to anything: a stock, your account, an opinion, a strategy on Research. All your annotations you ever made are shown in the general notes page where you will be able to also edit and search. You can access the general notes page by clicking the icon:
Stock notes are unique in the sense that they are "global". No matter where you added a note about a stock, it will be visible anywhere the stock is shown. Another feature of a stock note is that it is visible in the stock chart.