One of my pet peeves is that increasingly frequently, pressing Enter to submit a web form doesn’t even universally work anymore. Instead you have to tab to the submit button, and (depending on the web page) have to press Space or Enter to actuate it.

Another annoyance is that many web forms (and desktop apps based on web tech) don’t automatically place the keyboard focus in an input field anymore when first displayed. This is also an antipattern on mobile, that even on screens that only have one or two text inputs, and where the previous action clearly expressed that you want to perform a step that requires entering something, you first have to tap on the input field for the keyboard to appear, so that you can start entering the requested information.