I'm content with my life. It is financially and emotionally stable which is a massive help. Feeling trapped in stressful positions with little practical opportunity to make positive changes is very difficult.
I'm not in an exciting phase of life but little things give me joy and frustration along the way, usually in close succession. Connection with nature is very important to my well being. Semi-regular attendence at church is a good pause to reflect and consider different perspectives.
No one is going to live a perfect life all the way through. No one is immortal so unless you are the one to die prematurely, we will all experience some form of grief along the way. There are no guarentees of perfect health to yourself or people close to you. It is difficult when those unstable phases cluster up and don't offer respite to deal with them before the next hit.
I like Buddhist perspectives on life. Nothing is permanent and that makes it easier to ride through harder phases. Suffering is caused by desire, and acknowledging what is causing that emotional hurt can help to work with it even if it doesn't solve the underlying issue.
I look at SM and feel happy to see people enjoying their fancy holidays etc. I might know that they have a stressful job and are run ragged by managing childcare etc, but I'm pleased for the happy moment that they share. I'm content enough with my tent in a field, and confident enough with my own likes and interests not to feel jealous of other peoples' highlights. I lost a parent in childhood and I think that from a younger age than average, I have learned to live in the moment, but also viewing a bigger perspective on life, not just being swept along with the tide of what is current that we "should" be doing.
There is a mixture of circumstance, outlook and mental health at play which are not constants and are variable in how much they can be conciously managed.