And for as long as I've had one, not one bad weekend can't be fixed by a short ride.
[0] https://en.wikipedia.org/wiki/Learned_optimism#Seligman's_me...
He starts with testing where the patient rates their feelings such as sadness, anxiety, depression, etc. on a scale of 1-10 before every therapy session, then works through one of these events of bad feelings - what triggers it, why, trying different techniques to help get past it, and finishes a couple of hours later with the same test to see if the symptoms improved. Test-driven therapy, honing in on techniques which help people feel better quickly, and rejecting those which don't.
He works on distorted thinking patterns and practicing rebalancing them. e.g. when you feel bad in some way, some of these patterns might be happening: https://worksheets.ambrasta.com/wp-content/uploads/2019/12/p... can you notice them as they happen and use these approaches to change them when they happen: https://glassempty.files.wordpress.com/2014/07/10ways.png
His more recent work is on identifying and unhooking the thought patterns which resist change, which say "I deserve to be miserable" or "I should feel guilty it's my fault", or "my boss is superior so I have to feel inferior" and then developing techniques to change those.
It's a very practical kind of therapy - not ten years of talking, not digging through a lifetime of history, or making grand diagnoses, but what can help you feel better about a specific thing next week, this week, today?
Related, his Feeling Good podcast series - contains a lot of updated ideas and techniques since the first book was written - https://feelinggood.com/list-of-feeling-good-podcasts/
With regard to emotion, like I said, mindfulness isn't meant to eliminate emotions, or even eliminate negative emotions. If something makes you mad or angry, you may carry that emotion into later tasks. Mindfulness is about recognizing the anger, acknowledging it, but understanding not to project onto other things.
There's probably more to it, but I was trained in mindfulness by proxy of martial arts (that was the study) [1]. I never studied it outright and only took a Mindfulness Attention Awareness Scale survey a few times over a few years. The paper I linked might give you some ideas on what mindfulness is.
[1] https://journals.sagepub.com/doi/pdf/10.2466/22.23.PMS.116.1...
My personal experience with the book, and mindfulness in general, is that it has significantly transformed my life for the better. I say that despite the fact that my practice of mindfulness has been pretty poor, but I keep working on it.
I don't subscribe to what I would call woo woo thinking or philosophy, so I was pretty skeptical at first. However, the fact that this book was written by a medical doctor helped me overcome my skepticism. My initial attempts at mindfulness meditation, however unskilled it was, sealed the deal.
It has been incredibly helpful (beyond what I originally thought was possible) to use the techniques of mindfulness to be able to notice the thoughts and emotions I was experiencing, without judgement, and then gently, and purposely direct my attention towards something more positive or peaceful. I use the techniques, even if just a little bit, every day. It's helped my emotional self-regulation, my relationships, and my ability to focus on work. It's helped me cope with pain, and maintain resilience even when I was feeling particularly low.
There are lots of wonderful books on this subject. Another great one is "Happiness" by Matthieu Ricard (another scientist). Sam Harris talks about mindfulness extensively, so you might check his work, and his app (although the app is a paid service).