The worst are the sites that add additional text when you copy eg something like a quote.
Try to copy one from this site for example.
http://www.brainyquote.com/quotes/authors/a/albert_einstein....
Try to copy one from this site for example.
http://www.brainyquote.com/quotes/authors/a/albert_einstein....
"Please enable Javascript This site requires Javascript be enabled to provide you the best experience [for us]. Some features [like shoving crap into your clipboard] may not be available with Javascript disabled!"
It's not uncommon to find sites whose definition of "good UX" is exactly the opposite of what I want.