Also what those work colleagues don't get is that saving to be FI is not some long period of deprivation followed by finally attaining the brass ring. First, there should be no feeling of deprivation. Second, every single day you are gaining in financial strength which provides you with all kinds of options (like MMM's article on riding the wave of financial strength). Yes, the pinnacle is being completely FI and no longer needing to even work for a living. But along the way, being debt-free is one kind of financial strength many don't enjoy, having enough money to leverage when needed for certain kinds of purchases (like buying a house to live in or a rental property) is further strength, having FU money is even more strength, and so on. Imagine if those colleagues realized that by accumulating a large stash you are making $10k, 25k, 50k+ annually in passive income alone.
It's ironic that as you get richer, you find that you could afford those things the colleagues talk about without blinking an eye, but often you just don't care to. Then if you decide to make a purchase -- even a large one -- it's no big deal, no hand-wringing over how to finance it, and no guilt or remorse.