For a person aspiring toward spirituality there’s no greater enemy than Amalek. When Amalek takes over, we feel tired, confused and lose the importance of spiritual work. He takes away our desire to apply efforts to reveal the Creator and become like Him. We begin to find many reasons why this isn’t worthwhile doing. And this is called the power of Amalek.
He doesn’t come at us as an obvious or revealed enemy, but sneaks up inconspicuously and implants a feeling of tiredness, laziness, making spirituality seem unimportant. You can do a thousand different things instead of doing a very important, specific, and properly defined action that will bring you to the goal. You’re ready to do anything but that! This is called Amalek.
He doesn’t reveal himself as an attacker and a hateful enemy whom you know you have to destroy.
From the 1st part of the Daily Kabbalah Lesson 9/2/2011, Rabash’s article