Muruh (master) DiCheshbinuh (of accounting).

In The Life of Our Leader Rabbi Nachman, article 586 we learn:

“I (Rabbi Nussun) heard how one of the youngsters was lying in the room of Rabbainu o.b.m.. One time he approached Rabbainu o.b.m. and began to cry before him on account of his desire to be a kosher (-proper) person. And Rabbainu o.b.m. was already lying on his bed, and Rabbainu o.b.m. got up, and sat on his bed, and began to speak with him, and he showed him the way to this, and he also instructed him certain studies to learn, and he also instructed him that he should be from the “muruh dichushbinuh” (Zohar, vol. 3 pg. 178.), that is, that every night before he lies on his bed, he should think how the day transpired over him; if he learned and prayed properly on this day, he should give thanks to Hashem Yisburach, and should say to Him: “Praise and Thanks to Your great and holy Name for meriting me to study and to pray on the day that passed, somewhat to Your liking, and I entreat before You, Hashem my G-d, that You help me in the coming day tomorrow to increase in Your devotion, with more copious Torah (study) and prayer, and with more kavana (intention/concentration).” And if Gd forbid he did not learn and pray properly in the day that passed, he should confess and entreat before Him blessed He, and he should say: “Master of the World, I know that I was negligent on this day, and I didn’t serve You properly, not in Torah (study) and not in prayer etc., and now I implore and entreat before You etc. that You pardon me, and You forgive me on the past, that I didn’t serve You properly, and that You help me tomorrow, on the coming day, to serve Your devotions in Torah (study) and prayer with proper kavana and completeness to Your liking.”

In our time when there is such heavy depression prevalent, it is a good idea to also honor and fulfill a different way to end the day which Rabbi Nachman revealed in the Story of Trust (published in The Stories of Rabbi Nachman of Breslov and Saba Yisroel), mainly to make a little celebration, see there (also see the Story of the Seven Beggars, the mute beggar of the third day). ↑

The Sefer Chasidim writes (article 165): And why does the Holy One blessed He love the forefathers, because the entire day and the entire night, their hearts didn’t veer from contemplating the desires/objectives of Heaven, as it says (Proverbs 23), “just with the fear of Hashem the entire day,” etc. because the entire twenty four hours [in one order] they were not distracted from the desires/objectives of Heaven, even in a dream etc., see there.

The Ramban also writes something similar in his Iggeress Hakodesh, how their minds were bound to the supernal light without even a moment of interruption, see there. ↑

Here the Ramchal uses a play on words, spinning the phrase, “huloach vishuv” – back and forth, to “huloach vichushuv” – going and thinking. ↑

An allusion to this can be found in Rashi (Deuteronomy 20:1) who explains the juxtaposition of the Torah portions pertaining to properly conducting justice and to going out to wage war, that by virtue of the former there is guarantee the latter will be victorious, and he cites a verse from Psalms (119:121) to support this idea. Rabbi Nachman said that all of the Psalms should be interpreted into one’s own personal battles, trial, and tribulations, thus this would very much proport the words of the Ramchal here, that one who properly reviews his conduct judiciously, he will be victorious in his battles over the evil inclination. ↑

In Chayay Moharan – The Life of Our Leader Rabbi Nachman, article 440, Rabbainu said that even if one has nothing to say just “Master of the World,” this is also very good. ↑

In the Letters of Rabbi Nachman of Tulchin, published in Ullim Litrufah, he writes, “And even if one can’t speak but a few words, “Master of the World, have mercy on me.” The added words, “have mercy on me,” make it clearer that this is intended more as a prayer than as a meditation. ↑

Likutay Moharan II, Torah-teaching 96, brought in Outpouring of the Soul (article 4). There Rabbainu says one should speak this thing that he does have many, many times without limit or measure, and even to spend many, many days just with these words alone, this is also good. ↑

Rabbi Nussun was once confronted and challenged by the praises of a certain scholar who was profuse in 500 pages of the Talmud by heart, Rabbi Nussun retorted that his Moshelle (-R’ Moshe Breslover, the mentor of Rabbi Yisroel Karduner) can say Master of the World 500 times (Yisroel Saba, chapter of One Silence. To See The Blossoms of the Spring, chapter of Prayer). ↑

There are of course exceptions to this general rule. The main one being for the Tikun Klalli – the ten Psalms Rabbi Nachman revealed as a general comprehensive rectification, for this Rabbi Nachman himself revealed Divine Names that should be kept in mind when saying them.

From here we can establish that obviously Rabbi Nachman was not ruling out the holy practice of doing yichudim, rather he was making it clear that the quintessential devotion must be with simplicity and wholesomeness – each person according to their level, and the main thing is real dialogue and expression, and not to overreach and lose that personal perspective. ↑

And thought can reach higher than words, see e.g. Words of Rabbi Nachman 46. ↑

See also Likutay Aitzoas, Prayer 2, The main weapon of an Israelite man is prayer, and all the battles that a person needs to conquer, be it the battle of the yetzehr hura, be it other battles with opposers and adversaries, everything is through prayer, and from there is all his vitality,” see there. ↑

This is like the classic Book of Charedim writes (page 48, also included in the daily learning of the Chok LiYisroel, for the Monday of the Torah Portion of Meekaitz): It is written (Genesis 6), “With the Lord walked Noach,” i.e. he would do hisbodidus with his Creator, and he didn’t have companionship with people, or, due to his habituation to hisbodidus, even when he was in the midst of people they didn’t unsettle his mind, because they were as not in his eyes, and this is what the poet (Rabbi Avrohom Ibn Ezra, “Agadelchuh”) said, “When I stand in the midst of Your congregation Rock/Creator to exalt, to You I prostrate and bow (my) head and stature,” that is to say, that their company doesn’t encumber me to detach my thought from You, because the whole world is a flock of sheep, and He Blessed He is the solitary shepherd and overseer over every single particular etc.. ↑

A synopsis of this is teaching is brought down in Outpouring of the Soul, article 56, with more material on the matter. ↑