I am (morbidly?) curious how Thich Nhat Hanh is experiencing life after a severe stroke; he is around 93 years old and has been paralyzed and unable to speak for about 4 years now; we'll never have a clear view whether a lifetime of mindfulness practice has helped him make peace with this compared to other elderly stroke sufferers, or whether the damage to his brain has changed his experience a lot. I've sometimes felt that the only way to get through a massive life upheaval is to have prepared for it in advance - in more common geeky terms, "I have already planned a secret so I can verify if I ever meet my clone" is something you can only do in advance; possibly a state of being OK with dementia or brain damage and waking every day not knowing where you are is something you can only prepare in advance while healthy, so those habits carry on after the point where you need them but no longer have the wherewithal to create them.

But you can't be happy all the time, and shouldn't be.

Dr David Burns, psychiatrist frames it to patients that people can expect 5 days of happiness and 2 crappy days in a given week, and if you don't have 5 happy days you should adjust something, but if you don't have 2 crappy days, then you're bordering on manic and should adjust something the other way. But then he considers a few minutes of feeling bad enough to count as time to take note and adjust for it.

My take on this is that "you should be happy all the time" is the wrong way to look at it, more "you shouldn't be unhappy against your will, because of negative thoughts circulating in your head which you are ignoring and hardly aware of". Being aware of your thoughts so you understand why you are unhappy and then you are informed enough to take action if you choose to; but since a lot of the reasons for unhappiness are fixations on the past and the future, on the incorrect idea of permanence of the ego or disconnection of ego from rest of world, or sadness at being imperfect, then becoming deeply aware of these thoughts implicitly involves them dissipating away as you understand how ridiculous they are; and with the sad, depressing, distorted thoughts fading away, there's room for plenty of happiness in mindful pursuit of ordinary activities. Thich Nhat Hahn uses examples like brushing your teeth or washing your food bowl - these shouldn't be hurried through so you can get to the rest of your life, these activities are your life and you should be aware of your desire to hurry through them and be elsewhere which is making these activities feel worse than they are. You need to do them, you don't need to wish-you-weren't-doing-them-and-feel-sad. They need doing, you are doing them, you may as well pay full attention to them and enjoy doing them. Alan Watts says "Zen spirituality isn't thinking about God while peeling potatoes, Zen spirituality is just to peel the potatoes", and "mindfulness isn't an activity to do while sitting, mindfulness is just the way a Buddha sits (and the way a Budda does everything)".

If you're happy, can you experience the moving emotion of a really tragic movie?

If you're sad about not driving a Lamborghini and your startup customers leaving and your partner being angry at you, and depressed about ageing and your joints hurting, are any of those things helping you experience the emotion of a really tragic movie? Yes I say a person who is generally happy and content with life including all its problems can still experience the emotions of a movie. (But would they want to? Can a person who is happy and content really feel angry at treading in dog poop? Maybe they can, but would they want to feel angry about such a thing?).

Thinking about the future is a great motivator, and can make us happy. Oh boy, my birthday is coming up! I almost have enough money to buy that house!

Which is fine in a measured way - but do be mindful that this happiness is a fantasy about a future which has not happened, and might not happen, and almost certainly won't happen perfectly in every way. To be excited for the future is one thing, to base your happiness on being able to buy that house is to invite suffering when you hit an unexpected bill and the house seller pulls out of the market or someone else pays more, etc. Mindfulness as "be aware of your thoughts, don't let them push you around" rather than "get rid of your thoughts"