Everything gets boring to me if I do it over and over again for too long.
So yes at times Youtube does become boring to me as well and I just stop watching Youtube for a few days and then I'm no longer bored of it again for awhile.
I also get bored of the computer even though I make my living through blogging.
Thankfully I don't have to sit at the computer for as long anymore and I can go a few days without even touching the computer if I want too.
So if you're getting bored of youtube then just take a break from it for a few days and then you'll probably be into watching Youtube again.