There is Only This Moment
Contrary to popular belief, there is only one moment that ever exists, has existed, or will ever exist in the future --- and that's this moment.
This is not a semantic trick, an abstract philosophical notion, or some deep metaphysical Truth. It's simply the fact of the matter. The moment that you are experiencing right now, as you are reading this, is the only one that is happening.
This is abundantly clear in a PCE.
Walk through it with me, if you will. You are going to read this paragraph, and by the time you get to the end it will be the "future". Ok, so you're still reading the text -- is it still now? Ok, good, so we're going further down the paragraph -- it's still now? That's right, it's continuing to be now, and... here we are. We got to the end - it's still now, isn't it?
But this is "the future" that we were talking about just a moment ago. We arrived to "the future" -- yet it was still now when we got here, and it was now the entire time you were reading this. And the point where we started reading the paragraph is now "the past" -- but it was now while we were reading the beginning, wasn't it?
What's the Point?
After going through the above, it might now seem like this is something so trivially obvious that it's not even worth mentioning, let alone be something that's actionable.
The point of it, however, comes into play when applying the actualism method -- which is enjoying and appreciating this moment of being alive.
Say you are unhappy with a conversation you had in the past with somebody. You are currently upset about it. The point is that, right now is the only time you can be happy, the only time you can be enjoying being alive. And you are currently frittering away this moment by being upset.
You might say well, let me throughly go over the conversation, see what happened, see how to fix the situation, then I'll talk to them later, and once everything is resolved, I'll be happy then... This is precisely what the normal way to resolve such an upset is, and it is entirely missing the point, which is that this moment is the only moment that exists. The "then" that you are envisioning you will feel better in, does not exist now. It will exist, but it doesn't, yet...
Just like with the "walk" of reading the text above, the entire time from now to "then", it will be "now". It will be "now" the entire time. So by 'waiting' to feel good, you are doing nothing other than not feeling good.
To expand on it a bit more, you might feel that by ruminating over the conversation, planning what to say in the future, and envisioning a resolution, that you are currently actively doing whatever it is you can to get back to feeling good. But as by doing so you are essentially expressing the feeling of being upset, via thoughts and plans, you in fact are not doing whatever you can to get back to feeling good. The ruminating and planning is not getting you back to feeling good -- because the only time you can feel good is now, and you are currently doing something other than getting back to feeling good now. You are planning on feeling good in the future --- which is equally as silly as planning on feeling good in the past, because neither past nor future are actual now.
The only time you can feel good is now. And the key insight is to see that you do not actually have to resolve the material circumstances of your latest set of problems, in order to feel good now. You can feel good despite the problems still happening. That is, you can emotionally accept without intellectually accepting the situation. You can still resolve the situation, of course, and it probably makes sense to do so... but you can do so while feeling good instead of feeling upset!
The point is ultimately that it's just silly to not feel good. So, get back to feeling good first... and once you are feeling good, then you can see what makes sense to do.