In the month of Elul (just begun), we give special attention to examining our actions, making positive changes, asking forgiveness from anyone we might have hurt or offended, and granting others our own forgiveness; all in prep-aration for asking G-d’s forgiveness on Yom Kippur.
We might feel sorrowful — or believe that we should feel sorrowful — over our own wrongs (real or imagined). Van Gogh certainly portrayed that in his painting (above).
Regarding this, a social worker I know posed a very pertinent question: What does Torah teach about forgiving ourselves?
Torah doesn’t address the emotional details of blaming or forgiving ourselves as much as psychotherapy does (although Hasidut and Musar move in that direction).
In general, we’re disallowed from doing anything that’s harmful to ourselves. This includes encouraging mental attitudes that tend to sadden us:
“One must be very cautious not to fall into depression to the extent that it will inhibit the light of penitence from penetrating to the depths of the soul.” 
We’re told that we should always be joyous; needless remorse that saddens us is not only useless, it’s prohibited. Rav Kook [*], for example, says that remorse is only useful to the extent that it motivates us to change for the better. Once it starts depressing us, or limiting us in some other way, it is to be avoided entirely.
He offers a uniquely important insight, however, into where we should place our efforts:
“The focus of [t’shuvah] must always be directed toward improving the future. One should not begin by making the mending of the past an indispensible prerequisite.” 
“Forgiving ourselves,” then, should be emphasized less than learning from our mistakes and changing our future behavior. Parenthetically, it will often be much easier to “forgive ourselves” if we follow his suggestion.
Other teachers might agree with him on both these points. Of course, it’s not meant as an excuse to deny responsibility for our own actions, either. A truly healthy mind is always finding a legitimate balance:
“Everyone must have two pockets, with a note in each pocket…When feeling lowly and depressed…one should reach into the right pocket and find the words: ‘For my sake was the world created.’ But when feeling high and mighty, one should reach into the left pocket and find the words: ‘I am but dust and ashes’.” 
Some of our literature at times advises us to berate ourselves rather harshly. But even this is meant only when it can be used as a useful tool, not as something to needlessly depress ourselves, or interfere with our willingness and ability to make positive changes in our thoughts and behavior.
It also occurs to me that “forgiving ourselves” and being “forgiven by G-d” only seem like two separate things until G-d’s Presence is as real to us as our own. When G-d forgives us — i.e. when we truly feel our rapprochement with G-d directly — our self-forgiveness is simultaneous and automatic. Put simply, although we can forgive ourselves without necessarily feeling closer to G-d (which characterizes psychotherapy and other secular wisdom), I don’t think we can feel forgiven by G-d without in the same moment spontaneously forgiv-ing ourselves, too.
Some years ago, I prayed while depressed or upset about something I don’t even remember now. Underneath, there was an element of self-recrimination. I suddenly felt G-d saying to me: “Who are you not to like yourself? Is your judgement that good?” It was a genuine reproach, offered with love and humor. The depression lifted spontaneously at that moment, too. But what’s more — it changed my thinking incrementally about judging myself at all. Cumulatively, such experiences are how we grow spiritually.
We can look into hasidic and musar literature (in the wider sense of those terms) to find further comments about it. But in general, Torah (in the sense of the entire Jewish tradition) would be against any harmful state of mind. We forgive ourselves to free ourselves for greater spiritual growth — not to avoid responsibility.
I’d say that the best that psychotherapy teaches about this — needless sadness over acts you’ve already done is pointless, and interferes with your current functioning — is a good barometer of at least part of what Torah teaches.
To whatever extent we’re able to correct what we’ve done, we should do so. The Orthodox, especially the Hasidim, might consult with their personal rebbes as to what they should do specifically. Other branches of Judaism might leave the solution more up to the individual but the rabbi can be a guide there, too.
So, the answer to the question about “forgiving ourselves” seems to be: Accept responsibility, but employ remorse only to the extent that it can be used as a motivator for positive change. Sadness is useless.
Our relationships with other people are “dynamic” — constantly changing. Our relation to G-d is the same. Don’t let needless or excessive remorse interfere with the inherent peace and joy of that relationship.
Van Gogh’s painting, as artful as it is, need not represent to us the Torah-attitude about “facing our fate.”
Let’s enter this period before Rosh Ha-Shanah and Yom Kippur, then, with seri-ousness, and with joy, too.