Long breaks? Slacking off? Meh, amateur league stuff that doesn't really get at the core issue. And certainly not effective long term.
FU money gets you closer, and it's an important step along the way, but not quite the complete picture.
Don't hate your job. FU money is a great for this. If you're being asked to do unreasonable or shitty things then it's very freeing to be able to walk away. Just knowing that you have the option, even if you don't use it, can make a huge difference. What this really comes down to is knowing that you get to decide how much bullshit to tolerate. It's about not being stuck.
But also, don't love your job and don't aspire to love it. Many many people make the mistake of thinking they should love their job. It's a job you do first and foremost to make money. If you love your job then you're likely getting trampled on, working way too many hours relative to the time and effort. And the pressure to love your job is probably making you unhappy. Your co-workers are just that, co-workers also there to make money. Work is not family, not social life. You can and should get along with your coworkers, but be realistic and be intentional and ruthless about keeping your life and more important, your identity, separate from your job. There's a reason the big tech companies work so hard to integrate the workplace into every facet of life, and it ain't because they're altruistic.
Instead, be at the point of indifference with your job. Neither love it or hate it. Hold it with an open hand, where you can take it or leave it. FU money and/or having a large stache means you know you don't have to have that particular job, or any job, for an extended period of time. You will not feel stuck and be more impervious to the negative. You will be happier doing your job, taking pride in what you do for nothing more than the sake of doing it well. You'll be more likely to get promotions and raises because you're not attached, are open to other opportunities and willing to risk asking for raises and promotions. Part of the reason the rich get richer is that they have the option (power, really) to negotiate harder and press for more - instead of passive aggressive bullshit like slacking off they're making demands and getting higher comp.