For me, the biggest suck to web experience since I first started using it back when MSN came out (90s) is every page prompting GDPR.
Now if the GDPR could realistically do something about the tidal wave of spam I've got from pubs in random parts of England and Wales I happened to visit once while waiting for a train back when they were insisting on doing everything through an app that would be nice! I'm fairly sure most apps don't need to be apps at all, they could be websites if companies weren't desperate to inject analytics and yet another vector for spammy marketing into every interaction with them.