Sometimes it's unavailable - this isn't good. I'd like to know the reason behind outages, and be open to increased fees for increased reliability.
Sometimes I need to clear cookies to log in - This is a minor inconvenience, but it suggests bad practices behind the scenes. A site update either wasn't tested or was pushed with a known bug that wasn't clearly labeled. This is concerning for a bank.
I'm not sure how tied your hands are with integrations, but the pop-up windows for things like sending money are really irritating.
Feature requests for the website should be tracked seperately. They're specific and common enough to warrant their own category, and they impact every member, but I don't think these requests are currently given the weight they should.