* Тоска

> No single word in English renders all the shades of toska. At its deepest and
> most painful, it is a sensation of great spiritual anguish, often without any
> specific cause. At less morbid levels it is a dull ache of the soul, a longing
> with nothing to long for, a sick pining, a vague restlessness, mental throes,
> yearning. In particular cases it may be the desire for somebody or something
> specific, nostalgia, love-sickness. At the lowest level it grades into ennui,
> boredom.

_- Владимир Набоков_

Тоска is often translated to anguish or melancholy in English and lengsel in
Norwegian. The general term of sadness in both languages is also often used as a
translation of the word, although it far from captures the meaning of the word
perfectly.

There is something sobering about the feeling, it puts other experiences into
perspective. It is bitter-sweet, a reminder of what you have done, but can also
contribute to a hopeful perspective on the future.