My point was that there is no reason not to self-improve in that way.

I agree. I only wish to add two points: first, such self-adjustment is frequently unsuccessful (e.g. curing severe depression often fails or takes many years) and second, we should self-adjust to remove destructive, negative emotions (where possible) regardless of whether the emotions are "extreme" or are "justified by the facts". (There may be cases where on reflection we should not remove them, or not completely, but extreme-ness etc. aren't valid reasons in themselves.)