There's a set of thru hikers called 'purists.' Purists basically feel that for a thru hike of the AT, you need to walk past every white blaze while carrying your full pack. At some point after Trail Days (Damascus) and before the Shenandoahs, we decided to not worry about the blazes anymore. Our hiking philosophy morphed into what we've started calling the 'impurist' way of thinking.
We're still hiking more than 2000 miles, but somewhere along the way, we realized purists don't get to see some of the coolest things near the AT - simply because they have to walk past white blazes. For example, a lot of times there will be some other trail that junctions with the AT in two places a few miles apart. Usually these trails are called blue blazes. The blue blazed trail will be a side trail with waterfalls and beautiful scenery, while the AT section in between the junctions will usually be the usual green tunnel/woods. You have three choices as an AT hiker - 1) take the side trail and bypass a short section of the AT, thereby seeing the cool stuff 2) stay on the AT and not see anything but chipmunks and trees, or 3) go down the side trail, see the cool stuff, then come back and hike the AT. Otherwise known as 1) the impurist way 2) the purist way, and 3) the crazy purist way
To sum it up - we are of the opinion now that we don't have to walk past every blaze. As long as there's a good reason (like gorgeous waterfalls and swimming holes), once in a while a blue-blaze is better than walking on the AT simply because the AT has white blazes. Sure, we might do 2100 miles instead of 2180...but hey...(2180-2100) << 2100.
Next up: the impurists aquablaze the Shenandoah River!