Some days we are faced with reminded of the disappointing nature of our life or work situation and we are left with a sense of frustration.  These daily sufferings are part of the fundamental, unsatisfactory, nature of life itself which we work with in meditation:

The third noble truth says that the cessation of suffering is letting go of holding on to ourselves. By “cessation” we mean the cessation of hell as opposed to just weather, the cessation of this resistance, this resentment, this feeling of being completely trapped and caught, trying to maintain huge ME at any cost. The teachings about recognizing egolessness sound quite abstract, but the path quality of that, the magic instruction that we have all received, the golden key is that part of the meditation technique where you recognize what’s happening with you and you say to yourself, “Thinking.” Then you let go of all the talking and the fabrication and discussion, and you’re left just sitting with the weather — the quality and the energy of the weather itself. Maybe you still have that quaky feeling or that churning feeling or that exploding feeling or that calm feeling or that dull feeling, as if you’d just been buried in the earth. You’re left with that. That’s the key: come to know that. 

Pema Chodron, The Wisdom of No Escape: And the Path of Loving-Kindness