We, as human beings, are extremely adaptable. We are creative, we can design solutions, we can use the environment to our advantage. That is something worth celebrating.
At the same time though, we're extremely good at getting used to all sorts of unpleasant situations. And that's not necessarily always a good thing.
You get used to physical pain and after a while, that knee that was bothering you becomes normal. Without realising it, you stopped doing a few things that you used to do daily. Those terrible social situations that used to annoy you? Now you're able to tolerate them. That terrible relationship? I mean, it's not too bad after all.
"You'll get used to it" it's a phrase we hear way too often. And as I said, sometimes it's a good thing. Sometimes getting used to events in your life IS a good thing. But sometimes it just sucks. Sometimes you want to change something but for your damn brain, it's easier to simply adapt and accept your new reality.
And it's hard enough to notice this when you have a point of reference. You know what a healthy knee feels like so you have the tools to realise that no, your current knee is not just fine. But it's way harder to notice you've become accustomed to a shitty lifestyle and that you need to do something.
Life and mental changes are subtle and gradual. They're like a river, slowly carving its way across a landscape. You don't notice it at first but what used to be a small and straight creek, gently sweeping through a plane has now become a meandering river, deeply embedded into the surroundings, and changing its course now requires some serious work.