Being happy means you'll never feel like crap
It's no coincidence that a lot of these myths are cliches from fairytales, and nowhere is that more evident than humankind's steadfast belief in happy endings. No! Not that kind!
The "happily ever after" stuff just isn't real. To be human is to feel, and it's a guarantee that you'll feel disappointment, loss, anger, guilt, sadness, fear, conflict, embarrassment, frustration, and so on and so on. These feelings are universal; happiness is about being able to make space for ALL these shitty emotions, not just the positive ones. They’re not a sign of brokenness or pathology. They mean you’re not a robot or a psychopath. Nice work!
True happiness doesn't need any validation from external people or achievements
Just because achieving your goals won't bring you happiness doesn't mean that a total detachment from the world is a sign of true contentedness. Humans need connection, and it's not a sign of unhappiness if you happen to want a family or really take pleasure in getting a promotion at work. Don't confuse this with a romantic connection, though -- the essential thing here is that connection makes you more human, whether that's through platonic friendships, volunteering, stamp collector swap meets, a backgammon club, or whatever you enjoy.
Happiness is merely a state of mind
There are few things that get me more riled up than "inspirational" quotes like "Choose happiness" or "It’s all in your head." You know how that makes a person with depression or anxiety feel? REALLY FUCKING SHITTY.
Of course your outlook has a significant impact on mood, but so do hormones, neurotransmitters, sleep, exercise, diet, drugs, breakups, death, stress, transition, that John Cusack movie you can't stop talking about -- you get the idea.
You can’t just "choose" happiness. Rather than telling yourself it’s all in your head when you’re feeling anxious or low, practice self-compassion, hang around with people who won't judge you if you're not a ball of positivity, and consider all the other reasons besides "your attitude" that might be contributing to your mood.