This is a group of lower emotional tones I single out for a reason: they are not only toxic but very difficult to shake off. You can move out of fear or anger very quickly; just “pull yourself together.” You’ve done it often; you know it works. Fear may come back but it comes and goes quickly. So does anger.

But these lower emotions are notoriously steady and unrelenting. That is why they are so corrosive.

Definition: corrosive, wearing down and steady destruction; the power to cause irreversible damage; eating away; steadily harmful.

I am talking about melancholy, shame, guilt (blame) and regret.

Guilt is probably the “stickiest”. Once it has taken root, it is like trying to get rid of horsetail in your garden. You can pull and pull on the stalks but the roots will keep sending up new shoots.

Guilt is real, deep misery. When a person feels guilty for some effect, it seems that no amount of rationality and reassurance will convince them of anything other than their obvious blame. It’s a self-destruct thing and beyond all reason to the point where it is truly pathological.

Regret spoils all happiness. The problem with regret is that it sticks people to their past. They are wedded to something which can never happen, which is that the past be different. The past will never be other than it was. So regret is self-defeating.

Shame blocks any feeling of deserving or reward. Toxic shame is a feeling of unworthiness on some account. Whereas guilt is “I did bad”, shame is “I am bad.” It creates separation from others because, even if they don’t judge us, we judge ourselves. Shame is not simply a moment of embarrassment but it is the belief that our imperfections, our mistakes both past or present, mean we’ll never be good enough.

Melancholy comes from the Greek words melan (black) and choler (bile); hence black bile, which the ancients believed caused this mood. This is not just sadness or tears. Melancholy is a deep gloom that settles over and individual and blackens their entire perception of the world. Even potentially happy moments are marred by the blackness.

The sufferer sighs or wrongs his or her hands—but never laughs. That alone is destructive.

These days it would be grouped under depression: low mood, loss of interest or pleasure, feelings of guilt or low self-worth, disturbed sleep or appetite, low energy, and poor concentration. The statistics for that are pretty grim: depression is the number one pathological condition that is diagnosed, worldwide.

At its worst, depression can lead to suicide, a tragic fatality associated with the loss of about 850,000 lives every year.