[JepZ]

As the down voter did not care to leave a comment, I try to give an example:

For years we were seeing the burger icon (3 horizontal bars) as an icon for menus. It took quite a while until it became a well known standard to add some 'Menu' text next to it (as you can see it on the Laws of UX page).

So for years we had a pattern on most sites which was not optimal. Just using it because everybody else was using it, didn't solve the problem that a majority of users did not understand or knew the icon.