My bank’s new login page really needs to be a case study in a course on UI design.

Three or four seconds after the page seems fully loaded, with inputs for customer ID and password, an ad for one of the bank’s products will sometimes [not always] pop up at the bottom of the page. When this happens, if you are partway through typing your customer ID, that input *loses focus* and turns a warning shade of red because it has too few characters. You need to click it again to resume typing.

I've been conditioned by this punishment to wait a few seconds before I start typing my ID, but the ad doesn’t always appear, and the timing is variable, so ... honestly, did no human ever try using this before rolling it out on their customers?