Unhealthy Boundary number four is not speaking up when you have something to say.
I often hold back what I would like to say because I'm afraid that people with judge my opinions. Another problem I have is being afraid of sounding stupid. When I was a kid, I would get told off for asking "stupid questions". In retrospect, I was a curious kid.
I often had unwanted negative attention on me for no reason, so if I can help it, I would like to be as not noticed as possible.
Learning to speak up does take practice. If I never speak up people often insert ideas of what my actual personality is. Often wrong. People are often surprised that I can sing, dance and do yoga because "I don't look the type." Whatever that means.