1. One who isolates himself and separates himself from others, they attend to him from Above (t.n. Rabbi Nachman of Ttcherin's references show clearly that this attention from Above is to redress the persons sins. Examining the word Rabbainu used – 'mizdakek' in the holy books of the Torah, show that in fact this word is used to invoke action of obligation and redress, Rabbi Nachman of Tcherin who was a very holy, accomplished, knowledgeable Torah scholar, and also very much familiar with the traditions and teachings of Breslov, obviously was on the in on the meaning here. However a quick look at present day understanding of this maxim shows a complete misunderstanding – it is taken as a positive thing, as purification or some sort of grace. This misconception is based on the common knowledge of the high regard Rabbi Nachman of Breslov had for hisbodidus – secluding one's self in communion with G-d. However, just like in the second entry here on hisbodidus, where Rabbi Nachman of Breslov reveals that there is a way that hisbodidus can be harmful, so here too Rabbi Nachman is revealing that if in addition to one's hisbodidus he generally separates himself from people, this will bring upon him judgment and redress G”F. See Ramba”m, Laws of Repentance, 4:1 that seperating one's self from the public prevents one from repenting.
Also see Sichos HuRan, the conversations of Rabbi Nachman 81, that if a person would be completely alone, even though he may be bombarded with bad thoughts and even sin G”F, he would be filled with remorse and eventually would turn to a truthful path. However in the continuation of that teaching Rabbi Nachman seems to explain that this isolation is just to the exclusion of bad or misguided people.
Also see Sicho HuRan, the conversations of Rabbi Nachman 77, that a person has in himself elements of representation of all the 70 nations, and when a person is alone and not at peace with himself he can go crazy from the internal schism of these elements. However when a person is with others, the elements are spread out and championed accordingly to the other people who are most similar – free quick synopsis).
2. Through isolating oneself and setting one's heart wantonly, one comes to anger.