I was reading some article a while back, and as I read I like to highlight what I'm reading with my mouse, but that particular website decided that when I try to highlight text, the appropriate reaction from the site would be a tooltip saying that highlighting is not allowed... So I opened the devtools and copied the whole thing out of spite
At least they were being honest about the design decision by actually telling you.
Just as a matter of polishing my apps, I usually go through and make sure that pages that might be printed or PDF-copied will print well, that everything selects where someone might want to copy text, and doesn't select where they're clicking any UI element resembling a button. In other words, I try to make all text fields selectable and printable, and everything else act as a graphic (even if it has some text on it).
On some of my old sites I used to check for whether the document was in an iframe, and go into an infinite loop if it was. The trick is to loop/delay slow enough to not trigger the "script is not responding", but enough to make the browser hellishly unresponsive.
Back in the Flash days I had a cherry bomb I'd put in my code that would crash decompilers in a similar way, if it found _root.stage.parent. It would also phone home first ;)
