If you're doing AM full time then fucking off and doing that crap is the equivalent to taking a 30 min. nap at any other day job.
I can't talk because I'm a smoker and I find myself often taking smoke breaks, but I am always think AM during these breaks, and I often have some good ideas demanding immediate implementation by the time my cig is half done. If you're thinking AM, it's ok to not specifically be doing AM at that point in the day. Sometimes you need to take five and see the big picture and you can often find yourself starting to think outside the box.
However, fucking around on YouTube is just a plain distraction and should be avoided if you're trying to get any serious work done. Reward yourself with breaks after you've reached some hurdle or milestone throughout your day, just don't daydream and wander around or you won't accomplish anything.
Your competition is always thinking, if that doesnt scare the shit of you, I don't know what else will.