The key problem is that most contemporary web design does not follow any idioms. Idioms are conventions of design that are universally understood. Skillful use of idioms makes it much easier to parse what is going on on a given page.
Where we are with most applications is that they try to define their own idioms, i.e. their own icons, their own navigation patterns, etc. But this is very arrogant because they're assuming that the user has the time to build that familiarity with all those idioms. This is never the case.
Every day I use web applications from nominally mature companies, and they have totally different icon sets for the same actions. This is immensely distracting and hard to read. Every company sees an opportunity to define their own icons, when what they should be doing is using the exact same ones as everyone else because that makes it easy to understand.
https://essays.johnloeber.com/p/4-bring-back-idiomatic-desig...