I am an organisation of one person, just me. I've been using GCS with no problem for a few years. Today I've created a new bucket, and am currently using gsutil to populate it, with no obvious problems.
In the GCS web app I've just tried to click into the bucket via the Storage browser, just to verify it was being populated, and was told
Additional permissions required to list objects in this bucket: Ask a project or bucket owner to grant you 'storage.buckets.list' permissions (e.g. by giving your account the IAM Storage Object Viewer role).
Ok... but I created it? Whatever, I'll click on the menu button (three vertical dots) next to the bucket name and select Edit bucket permissions.
You do not have permission to view the permissions of the selected resource
Right...
Any ideas?!
You figured it out based on your comments. To reduce future guesswork, a really good reference exists for figuring out what roles get which permissions.