My personal "ah ha" regarding ATG was seeing the wiki that suggested different cutting angles for the three different kinds of pass ...

30 degrees of angle for WTG
15 degrees (I think, or maybe 20 degrees) for XTG
5 degrees of angle for ATG

The 30 degrees really improved my WTG, and boy, the 5 degrees made a 100% difference in both the ease of the against the grain, and the facial comfort afterwards. I think the theory is that you almost want to be flat for against the grain as you are trying to slide the blade under the lay of the hair, whereas with the WTG, if you laid the blade flat you would slide over the lay of the hair.