Breakfast Topic: Is RNG good?

I spent several years trying to get the Brewfest Kodo, and I never did until this year. One of my friends has been running Siege of Orgrimmar nonstop since it debuted over a year ago and he still doesn't have his Dark Shaman transmog set. I'm sure we all similar stories of RNG, whether it be Warglaives, parts of the Bindings of the Windseeker, or a mount off of a specific boss. It comes down to whether or not you can get it to drop, and sometimes, you just plain can't. Similarly, there's BiS pieces that you may actually need to perform adequately, or tier pieces, or that one weapon to get you out of the last raid's gear. We've all been at the mercy of RNG? But is it a necessary evil, or perhaps even outright good for the game to put us through these moments?

I've heard the argument about how the feeling of relief when it finally does drop helps keep us playing. I don't know how valid I think it is, but it's worth keeping in mind. Do you think it's right? Do we need that crushing stick of not getting that thing we want to keep us reaching after the carrot of finally getting it? I know one thing - now that I have the Brewfest Kodo, I never want to see Coren Direbrew again.