The nature of our heart is such that whenever it clings and grasps there is agitation and confusion. First it might wander over there, then it might wander over here. When we come to observe this agitation, we might think that it's impossible to train the heart and so we suffer accordingly. We don't understand that this is the way the heart is. There will be thoughts and feelings moving about like this even though we are practicing, trying to attain peace. That's the way it is.
When we have contemplated many times the nature of the heart, then we will come to understand that this heart is just as it is and can't be otherwise. We will know that the heart's ways are just as they are. That's its nature. If we see this clearly, then we can detach from thoughts and feelings. And we don't have to add on anything more by constantly having to tell ourselves that "that's just the way it is". When the heart truly understands, it lets go of everything. Thinking and feeling will still be there, but that very thinking and feeling will be deprived of power.
