If you allow others to mistreat you, allow yourself to get out of shape, don’t bring your best to your career or relationships and generally don’t have any standards of what you will and will not accept in life, then you will almost certainly have a low quality of life. Raise your standards and watch your life improve almost instantly.
How you look, how you treat yourself, how you keep your household, how you raise your kids, how you allow others to treat you are all critical standards. Importantly, once you establish and enforce these standards, others will realize that you won’t accept less and will treat you accordingly. Respect yourself and so will others. This will result in a near-instant increase in the quality of life (though you may lose some “friends” or colleagues who never respected you in the first place). Get fed up, disgusted and intolerant of any low standards.