It could be the difference between internally and externally focused people. Internally focused people don't need external factors to validate themselves.
http://www.myersbriggs.org/my-mbti-personality-type/mbti-basics/extraversion-or-introversion.htm
I'm a mix of both types. For my internally focused activities, I need ample amounts of unstructured time. This is something that's hard to do while working full time and spending most of the weekend catching up on chores, family responsibilities, and keeping the social life active. This is why I would like to FIRE so I can focus on these activities which take a back seat in my non-FIREd life.
For my externally focused needs, work may provide some of this, but I feel as I get older that the externally focused activities I'd like to get more involved with have little to do with work. I can get this plenty with my social circles, volunteer efforts, participating in sporting events, planning travel. So, again, my non-FIREd life forces me to spend too much time in externally focused activities I have less and less interest in as the years go on...plus lack of variety being forced in similar activities from Monday to Friday. So I am out of energy to do the stuff I really want to do.
I'm finding I have less and less motivation to get up in the morning to get myself to work. However, I'd happily get up early to go on a nice bike ride, catch a flight to go on a wonderful trip, etc. So I have the reverse fears from the OP and I keep sleeping past my alarm clock and rushing in to work. Being at work is what drains me.
Daisy...
YES!
I am an ENTJ...And I'm very extroverted (90% I think). Maybe what you and others are trying to say to me is that I need to find other external structures/systems of validation? I just don't know what those are since my social circle is pretty much based upon military friends and/or other people with 9-5 jobs. Is it just a matter of building a new circle when FIRE?
spartana...the lake analogy is a good one, but for me it would simply be a race of some kind that would motivate me. Anyone could just go run 26.1 miles, but why do so many run an official marathon race?
Such an interesting conversation! I was an ENTJ for many, many years (now the T and the J sometimes show up as F or P). I am extremely extroverted as well, but not very competitive (actually, I am competitive, but I hate the way it feels, so I don't compete). For me, the only way to get me to row across that lake is for someone to come with me, so we can enjoy the journey together.
I NEED structure, and internally-imposed structure doesn't work. I am, apparently, not the boss of me. So if I set a deadline, but it's mine, I know it's not real and it doesn't motivate me. For me, it's all about other people, and that's where a job or some other external structure is helpful.
For example, when I was working on my Ph.D., I did pretty well through the coursework (and particularly well with professors who wouldn't accept late papers). Got through exams fine by forming a study group--I didn't study at all on my own, but discussing concepts with other people was fun and was sufficient in terms of studying. But the dissertation damn near killed me. I just couldn't get traction, because it was a made up project that no one cared about but me (I wasn't working for any professors). I procrastinated, made no progress, even dropped out because I just couldn't do it.
Then I did some contract work for a company and I saw an opportunity for a project, which I pitched to them and they accepted. Now, because someone else cared, and they funded the work, I blew through it, wrote up a nice report, presented results to the executive committee...and still didn't write my dissertation. Again, lack of external structure and expectations.
In order to actually get it done, I had to piggy-back on someone else's discipline. A very good, very disciplined friend of mine was studying for her CFA. We booked a room on the fourth floor of a women's club, a room with two card tables, two chairs, a lamp, and nothing else, not even internet access. We met there at 8 am every Saturday for six months and worked silently until 4 pm, breaking only for lunch. I never, ever in a million years would have left the house at 8 am every Saturday on my own, but because I was meeting her and didn't want to let her down, it worked. And if she'd had a personality like mine, it never would have worked, because we would have chatted and jointly procrastinated the day away. And if there had been any distraction at all in that room, internet access, an interesting and ever-changing street scene, a comfy couch, a magazine, anything at all, I wouldn't have finished.
And that is me--it seems almost pathological and very persistent. It's why I've never had any interest in being a SAHM--I would be a disaster. I piss away most weekends. I have all kinds of ideas and projects that I want to do, but I don't. I love scrapbooking, but only do it when I schedule time with a friend. I never go on a walk by myself, but I will reliably meet a neighbor at 6 am every day. That's why work works well for me, as long as there are some real deadlines and someone who cares about my productivity. I don't need to be micromanaged, but I need that external accountability (in the case of my new job, it's the board and committees).
So why not just keep working forever? The issue is, as I get older, I want to do my own stuff more and more. And though the structure and external expectations work well for me, I'm tired of the majority of my energy and what discipline I do have going to work and not my personal stuff. And, I want to see what would happen if I had long stretches of time in front of me...would I eventually find ways to take some of the energy and discipline that work requires and apply it to my own life? Or would I just languish forever, unmotivated and depressed? Inquiring minds want to know!