When I was in my early to mid-20's I put up with a ton of boredom at work because I knew the industry I was in would pay better than anything else I could do without going back to school and training for a completely different field. I spent 40 hour work weeks with no phone, no internet access, trying to look busy, and feeling absolutely miserable.
I can always look back and wonder if it was worth what felt like several years of torture but I already had early retirement in my head when I was coming out of college, so I knew that career was my best shot at complete control of my time when I was young. And here I am 34 and FIRE. I can't really say whether it was worth all that pain because I don't know what my life would have been like had I just given up the ghost. Maybe I'd be a successful business man. Maybe I'd be a bum. You could drive yourself crazy wondering about the lives you didn't live. Knowing that I'm free at 34, I'm okay with what I sacrificed to be where I am today.
I think this is one area that I could question if early retirement might have hamstrung me early on. If I was just a guy thinking about working into my 60's, I'd have for sure dropped those boring jobs like a bad habit and found something I enjoyed more. My wife and I were frugal be nature so I think if we didn't have a big income we'd have still been okay because saving was so ingrained for us. Hell, maybe we'd still be FIRE but instead of planning to live on 40k a year we'd be comfortable getting by on 25k because we're even better at knowing what basics we really can live on, and what is fluff.
One thing I did learn early on is not to let anyone push me around. I always worked hard and felt that if I was doing my best, then I could have my principals and if anyone disagreed with that then I either win because I'm a harder worker, or my best isn't all that great because I'm just not a good fit for that role, in which case I should do something else anyway.
So I guess what I really agreed to early in life is being locked into that high income all the way to FIRE, like a horse with blinders on. In FIRE, I would never agree to a single thing in my life that I chased no matter what. There are simply times when the effort is not worth the reward, no matter how we'd like for the end result to be what we want.
A HUUUUUUUGE thing for me in FIRE is that I thought all that freedom meant I'd have total control over changes we were making and that they would be easy because we were FIRE. We planned to make so many changes in an 18 month span that it took panic attacks and therapy sessions for me to realize that no matter how in control and easy you might think big life changes can be (because you're FIRE), there are emotional elements to these things you can't just put in boxes and move around like a machine. To that end I now try to pay extra attention to the broad strokes of my life, feeling them out, instead of just assuming I'm the master because I have complete control of my time. I think this is something engineers tend to overlook because we're so focused on the efficiency of the mechanical aspects of a task.
Now that I've dealt with my self-created demons I understand change much better and I'm very excited about the additional big life changes that I know will be coming as we start a family, begin international travel, etc.