Believe that loneliness really is bad for your health and you will become unhealthy.
Sometimes, the best thing for a person is to be a "loner" and learn to be satisfied with who they are. Society usually isn't satisfied (does not "approve of") with a person being who they really are (does not approve of individuality). Individuality does not VALIDATE the world's pettyness, hypocracy, and fallibility. Many people (strangers) will sense that a loner is OBJECTIVE and not IMPRESSED by their SUBJECTIVITY (smiles, flattery, compliments, etc.) and will resent this.
"Loner" is not the same as "LONELINESS", but because of these little snippets of worldly wisdom ("Loneliness is bad for your health") and our willingness to fall for them "hook, line, and sinker", we end up making ourselves unhealthier than we actually should be physically (power of suggestion, mind over matter, as "I think, therefore I am").
Being a "loner" is hardly ever antisocial, persistent nastiness is ("loner" simply means "not impressed by all of the pettyness, hypocracy, and fallibility"). Having an interest (especially MANY) in life is NOT antisocial, enjoyment of getting to know and understand a person's life and their troubles/concerns is the exact opposite of antisocial.
There will tend to be a [somewhat well deserved] feeling of arrogance (from independence and self-sufficiency, after all,..."We are not amused"/impressed), but an inborn sense of humility is ever present. Loners will not "suffer" (because they know they don't deserve to) and will simply "ENDURE" hard times and feel the "sensation" of their affliction (pain is emotional/subjective).
We each should be so lucky as to know a "loner", and they themselves are unaware of the riches of life they hold in their hearts and minds.