Somebody can honestly live with peace of mind. Everything is a conscious decision. With enough practice, even the most difficult of achievements can become second nature. Play soothing music, exercise daily, eat healthily, jump from jobs when you realize your boss takes you for granted, pick an easy-going spouse and keep a watchful eye for when to get rid of them. The list goes on regarding ways to chase all forms of mental and physical stress. The majority of humans with high blood pressure actively contribute to the condition. I've hardly seen any who doesn't fret over unnecessary things or quick to grow anxious from the simplest of conditions. Before the creation of money, humans were at peace with their statuses in life. You will always find a way to survive if life-threatening ailments don't befall you.
Parents get annoying when older. It's no wonder people are meant to live their independent lives separately. As an adult, you can quantify how much they possess knowledge-wise and see areas where they lack. The problem is old dogs can learn new tricks — though slowly — humans will always resist change from what they were familiar with. Newer and convenient methods exist to do the simplest of tasks yet parents will stick to the only form they know because it defines them as people. My grandma will never drop her belief in witches despite never seeing one all her life.
Disregarding the existence of the supernatural means she wasted nearly a century on earth. Oh well, every new generation is more exposed than the last. Very few of us now adults will compete with the newly born generation into old age. Nature always guarantees it with the slow decline of faculties as one age.