I spent several hours of my first day of FIRE at the mechanic getting a bum tie rod switched out. In the days of yore (as in "Pain in Yore Ass") such forced idleness would have driven me ape-hockey, but I found myself perfectly contented to hang out, drink free coffee, read a book, and so forth. Towards the end the service department cashier and I were telling each other dirty jokes whenver the boss's back was turned.
Now, six or so months later, friends who see me for the first time since then are telling me I seem much more relaxed and fit. Thinking about myself back then is like seeing my own face from ten years back on fuzzy late-night cable.
Expect the first day to be great, and expect the subsequent ones to be even better.
Ed