Corporate drones who live the typical "make good money, spend all of it, and then some" American lifestyle will never understand.
When I was around 39, I started a new job. At the end of the year, I had the tradition BS "evaluation" where I had to start with a "self assessment." One of the questions asked "where do you see yourself in 5-years?" I thought about filling in the traditional buzzword filled, insincere, corporate bull crap (something like "I want to achieve synergies using XYZ corporation paradigms to better serve our clients and lead XYZ corp to global domination), but instead I decided to be honest and wrote "I'll be retired and laying on a beach in Cancun sipping a Margarita."
Needless to say, I was excoriated for "not taking the process seriously." At XYZ corp, evaluations took on almost a religious level of seriousness, and since I, in their opinion, dared to mock the process, I was clearly a poor employee with a bad attitude. I tried to tell them that I was serious, I would be retired in 5 years. Then they really got pissed about my "bad attitude" and told me to write a real goal. So I copied and pasted some BS out of the corporate manual.
I actually ended up retiring earlier than I'd planned- probably so I could avoid another "evaluation." :)
Most people just won't get it. They'll tell you it's impossible. Well, it is impossible for them, because they are undisciplined idiots. That doesn't mean it's impossible for you. Set the goal, work hard to achieve it, and enjoy the rewards for 5-, 10- or 20-years while the idiots who said it was "impossible" fight traffic every morning and trudge into work so they can pay off their debts...