Many of Bach's works lack tempo markings, so we infer their character and mood from the tonality he employs and determine the tempo accordingly. While some pieces are entirely transformed by tempo, others retain their fundamental idea regardless of whether the tempo is fast or slow.

This particular fugue is not one whose mood changes significantly with tempo; it remains largely consistent whether played fast or slow.

This fugue is, at the very least, not an expression of sadness. The author's attention was drawn to the chromatic progressions Bach employs. While chromatic progression is not particularly noteworthy today, in Bach's era, it was considered a convoluted, even taboo, expression, with descending forms often associated with the expression of sorrow.

In measures 5-6, while the tenor presents the theme, the soprano descends chromatically.

The notes are A♭, G, G♭, F, F♭, E♭. Try playing this alongside the theme, for example, with the notes A♭, D♭, G, C, F, following an alternating ascending and descending contour. This should also sound fitting, and this version is more optimistic.

While Bach's descending chromatic progressions are found in many of his works, in the case of this fugue, the author believes they represent not 'sadness' but rather fantastical depictions such as 'elegance,' 'mystery,' 'dream,' or 'illusion,' and are not expressions of emotion. Furthermore, the author considers this akin to the world of E major or B major that Bach employs—something not direct, intangible, and otherworldly.

Therefore, at least when the chromatic progression appears paired with the theme, avoid strong expressions.