I like your mantra very much. Hard disagree on emotions being wrong though. I am glad i learned to view emotions as messages from the more archaic parts of my brain.
The ones we label as positive come up if we do something that aids the survival of our species. Examples would be pleasure derived from food or sex.
The ones we label as negative are very important IMHO.
To prevent harm to ourselves we need Fear, it is a good friend. My theory is that anxiety disorders are like an allergy of the mind. In our super safe world our Amygdala has not much to do, very few (if any) predators around. But it stays on the lookout and reactions to small (or imagined) threats are totally out of proportion.
The rise in depression for me is a symptom of feeling lost/uprooted. If we take the theory that we evolved to live in groups of 100-150 individuals, that we all knew and worked with to ensure survival of the group, as basis and compare our modern lifestyle to it, we come out as extremely alienated from our nature. Even animals commit suicide if they see no way out. Put a scorpion in a ring of glowing embers and it will kill itself.
The root of anger is fear IMHO. Anger is there to ready us to fight in case of a real threat to our life. Nowadays anger rises in situations challenging our worldview, questioning our distorted view of ourselves or our status within the group. My favourite one is getting angry when observing behaviours in others, which we dislike in ourselves. It happens even if we are unconscious it. When i get angry about behaviour of others, i sometimes remember to ask myself if i act the same way.
The fight or flight situation leaves a third and fourth option. Freezing like a deer in the headlights, experienced it once myself. Read somewhere, that some predators only detect motion.
Anger might be expressed as (physical/verbal) violence against others. If it does not, it can turn against yourself and lead to depression.
The most healthy option i think is to accept your emotions and use your anger as motivation to change something for the better.
Following Proverb helped me to accept my emotions:
"Treat your feelings like a guest.
Open up, attend to their needs and say goodbye when they leave."
Another useful one:
"What you fight gets stronger." - Siddhartha Gautama
(edit) formatting, add anger