That title may be misleading: I do care about lots of things. I care about my family, extended family, and relationships. I care about my friends. I care about my home being reasonably orderly. I care about being presentable in public. I care about doing a good job with my clients. I care about God/Jesus and the Bible. I care about my country.
What I've learned not to care about is what everyone thinks about me or keeping up with the Joneses. The less I care what others think, the freer I am just to be me.
You don't like my opinions? That's fine, they're mine anyway.
You think I need to have my kids in every sport, after-school, and church activity? We don't value rushed evenings, so no, thank you.
You think I need a newer, nicer car? Unless you're gifting it, you have no say.
You think we should eat out more? It's our budget; we decide, not you.
You don't like my hair? Be glad you don't have to wear it.
I've learned that no matter what stage of life I'm in, someone will disagree with how I/we are living, working, schooling, parenting, "churching," exercising or not, eating... There's no end to the variables.
Being caught in the trap of worrying about what everyone else thinks will lead to a harried, frazzled schedule as you try to do everything you "ought" to do.
Equally bad is the financial strain and/or debt you pick up as you try to buy the approval of people that don't really matter long term.
Before buying the next shiny item, or volunteering for the next shiny project, ask who really cares and why you would be doing/buying it. Really weigh the options of what is good for you and your family--for now, and for the future.
I know in the end, I answer to God for how I've lived my life.
P.S. This is a two-way street. I have to keep my mouth shut when I see others living life differently than I would choose to live.