MS is massively variable. At one extreme, there are people who don’t even know they have MS because their symptoms are so mild. At the other extreme, there are people who only live a few years post diagnosis (MS is not considered a fatal disease, but it kills nonetheless). The majority of us are somewhere in between.
Do we enjoy life more than people with HA? I have absolutely no idea, but I would imagine that there is some benefit in knowing what’s wrong with us and having the support of medical teams, meds for symptoms, etc. However, you should not underestimate the difficulties that MS can cause: pain, fatigue, bladder and bowel incontinence, numbness, swallowing difficulties, vertigo, spasticity, emotional and cognitive problems, blindness, epilepsy, sexual dysfunction, etc. Yes, we learn to manage a lot of this, but it can be incredibly difficult at times. Every relapse takes something from us. Every year takes something from us. We learn to reinvent ourselves as things are no longer possible: change hobbies, change jobs, change friends, change houses, etc. Slowly, our world becomes smaller. It’s possible to adapt and find joy in the new things, but it’s never easy.
But it could be worse.
We are still here. We have a challenging life, sometimes almost impossible, but we can and do learn to manage symptoms and get the most out of our lives. It may not have been the life we planned, but it can still be good. That’s why I always say on here that MS is not the end of the world; that we can still have long, happy and fulfilled lives: because the vast majority of us will live a normal life span, see our kids grow up, hold our grandchildren, travel, party, laugh, love,… A lot of us do it with wheelchairs and crutches, wearing continence pants, popping pills for pain and spasticity, etc, but we do it.
As far as who posts on forums like these, it depends on the forum, but they are not a good representation of people with MS because most people with very severe MS will not be using forums because they won’t be able to (although their carers might) and most people with mild MS won’t be using the forums because they don’t need to. Of the rest of us, only a tiny proportion use forums (remember that there are somewhere in the region of 100,000 MSers in the UK) and we are the ones with the internet savvy and the time. One thing is for sure, the people who post on here do not all have mild MS; many are very badly affected. Perhaps, as you suggest, we just don’t complain as much.