If I told you that tomorrow you would become paralysed from the neck down, most people feel a modicum of panic.
Won’t life be miserable?
Yes, it almost certainly will be, initially. But the evidence suggests (think I was exposed to it by Sam Harris first) that after some period of time, maybe months or maybe years, many people that suffer this exact issue are back at the same ‘happiness level’ they were before.
However you wish to define that.
It appears we all live our lives in a constant state of regularity, irrelevant of external circumstances. Partly dominated by our DNA and partly dominated by our outlook on life.
Thankfully with effort and consistency we can improve our perspective. It does take just that though, effort.
As with all things in life.