People really need to ask why knocking a mob out of AoE damage circles, out of melee range or out of line of sight is a bad thing? Are we really at the stage where we have to explain basic mechanics to players because they can't figure out the obvious issues for themselves?

...yes, it's annoying. Save your knockback skills for the few times they might actually come in handy, like knocking a mob TOWARDS your tank after stealing aggro or INTO a DoT field rather than irritating everyone else in the team for your paltry DPS.