Okay.... the Vatican is no place for sissies.  I mean, you have to gather up all your reserves, your nerve and your joie de vivre (even if your joie is running on low) in order to cope with the MILLIONS of people who pack St Peter's Square, the Vatican museum and the Sistine Chapel.  It is a RIVER of people, each person as tired and cranky as you are.  Remember the sacred and profane comment from a previous post?  Multiply it by a zillion.  Here you have exquisite and priceless treasures and swarms of people trying to get a glimpse.  After a while, it's all just "ABC"... a saying I learned from a British couple years ago on a trip I took to the Balkans.  "Another Bloody Church".... yawn.  
What a shame!  There is just SO MUCH and it's all so incredible, that by the time (about 3 hours) that you get to the Raphael rooms you just want to have Life Flight come pick you up no matter what it costs.  Alas.
But it is all truly Divine and FABULOUS and you can't help but take a selfie... which is just TOO vulgar.