This "Living in the moment" stuff has depth such that many books have been written on it. It is one of the premises of mindfulness meditation, and Buddhism thoroughly explores this.
The summary is that you will be more satisfied if you are not continuously ruminating on the past, or anxiously anticipating future problems, but instead focus on your immediate happiness. e.g. Right now you are comfortable, not in any pain and surrounded by interesting things. Enjoy this, and don't worry about some conversation you might be having later.
Living in the moment is somewhat counter to striving. It's hard (maybe impossible?) to be a builder and a creator without spending some time ruminating on the last and future.
I think it depends on whether you want to feel like a good person, or be a good person. Living in the moment lets you feel better, because there's less to consider. Constantly examining yourself and those around you allows you to better react to those surroundings (even if some people don't act on it for various reasons, one of which might be getting too caught up in the examining and never doing).
Like literally every single thing in life I can think of, the truth is likely that moderation is key, as too much to either end of the spectrum is problematic.
This is definitely not true, at least most people don't experience it this way once they learn meditation/mindfulness/etc.
What happens instead is that if you are in the moment, you can much more easily see and feel which things actually exist in the current moment for you to consider, and to actually react to those surroundings that actually matter, instead of those that have been served up by the internal dialog which is based usually on worries, fears, ego beliefs etc.
Living in the moment does not make you live like an animal. It makes you appreciate and focus on that which truly matters for you, instead of distractions that a constantly thiking mind always throws at you and makes you feel like everything is says matters and is very important.
Those things that are truly worth considering, already exist in the moment. If you have a real need or want to do something today - it will be in the moment and it will present itself. It is a total nonsense that a person "living in the moment" can never complete any complicated task, accomplish a complicated goal or plan for the future when that is required. - And that is being a good person, not simply "feeling like one".
I would argue that perhaps your idea of living in the moment is more like mostly living in the moment. To truly live fully in the moment would be to react to stimuli as they were encountered, wouldn't it? If so, then to truly live in the moment would be to ignore most the ramifications of what you say or did, beyond what you could internalize, as to act without forethought is to strip away all we do to try to tame our less desired instincts.
That is what I tries to express by talking about moderation before. At one extreme you have what I outlined above, and at the other you have the person who always seems absent minded because they are always thinking about something else, and are rarely if ever giving their full attention to what's going on in front of them and around them.
I think when most people say you should "live in the moment" they are actually espousing moving that direction on the spectrum, which can be beneficial, even if reaching the end of the spectrum likely isn't. The point of all this is that being more mindful of your surroundings and living in the moment is probably useful most the time, until it isn't, because you've gone too far, where too far depends on the location, company, and circumstances, so there's no real "correct" answer.
The reason I even broached this is because it was already alluded to in this exact same thread, with:
I think it's a question of balance. I was too far on the side of not living in the moment, and spending lots of time on what-if scenarios. I think that I might have veered too far to the other extreme now, and my capacity for empathy is suffering a little.
I can relate to that in some respects, even if only for aspects of my personality. In letting go of always being too overly concerned with exactly how I was perceived and interpreted when I was you to being able to let some of that go later in life, I noticed times where my not making sure to explain myself in extra detail probably left people thinking I was dismissive of their concerns (and there are probably plenty of times where I don't realize I was dismissive of their concerns, and I'm willing to bet that's more often now than in the past).
If it is 10AM and I need to plan for my meeting at 3PM, and I need to consider the needs of the person I am going to meet - all of these details exist in my mind "in the moment". I can use those stimuli in the moment to plan out everything I need, in the moment. Even though I plan something in the future, I move those plans in my mind which exist there as a moment, as images or words or etc.
Once you start practicing mindfulness or meditation, you very easily see these distinctions. Yes, there is a way to use those concepts in a literal sense in which "in the moment" would mean that you can never consider anything else than your immediate surroundings. However most spiritual teachings or meditation retreats or people who say that this thing has helped them in their life, mean it in a more practical way.
Perhaps "being in the moment" is not the best phrase to really explain what they mean here and there is a lot of space for confusion and misunderstanding. But it is just the phrase that they usually use.
I think that this is a false trade-off. Being "in the moment", or "present" doesn't mean turning off your brain and not planning for the future. It is possible to be present while you are planning for the future.
This amounts to, when planning, not being overly invested in emotionally anticipating the outcome of your plans. (Both good or bad, as anticipating the good will hurt your ego when the plan fails, and dreading the bad will hurt you now.)
I can comment on this for my wife who suffers from anxiety.
She is very good at planning because she needs to feel in control all the time. You are right that when things don't go as planned and the pressure ramps up she loses her control and makes poor decisions or no decision at all.
It's interesting to me as I am on the opposite side for most of the time.
