Because of the after-effect. No matter how much you cringe away from that foul-tasting thing, you know in your mind that you won't feel better until you take it.
Some situations in life need an emotional medicine. You may not like to face them, sometimes you don't like what it says about you, sometimes you don't want to believe that this has happened, but somewhere, in the back of you mind, in that little logical nook, you know you have to accept this situation like a bitter pill or you won't get better.
It takes courage, it takes fortitude, it takes self-realization, most of all it takes an acceptance of defeat. You cannot just face the Sun and deny the existence of shadows, you have to accept them both.
Why am I talking about all this nonsense that you already know? Because I am down with flu right now and it so happens that I am taking both pharmaceutical and emotional medicine right now. Because I know well, that without taking this medicine, I would not be able to put this thing behind me and move forward.
Once the medicine does its work and you can move on, what then? Back to work! Oh yuck! Let's not talk about that today, I am already nauseous.