A lot of these shy traits are learned behaviors too. My mother was very shy with outsiders and struggled with social anxiety, I believe it was in part of the cultural clash she struggled with. I feel like I picked up some of her introverted behaviors. For example, I have inadvertently came off cold or standoffish to people without realizing It until It was later pointed out to me. Therefore, no
I don't think introversion is always attributed to fear. Personally,I would consider myself outgoing however, first impressions may not always appear what they seem.I can't tell you how many times I have heard this statement about me: " I thought you were this, but now that I got to know your really cool".
I would argue I am ambivert, and more times than none I am just reserved by default. It is most likely however, If I am not interacting with you it's probably because I really just dont want to talk to you...
I think first impressions aren't always the best ones.We are all different and we interact differently. I say, take the time to get to know someone, no matter how different they are from you. Open up and give them a chance, you never know how much they will impact or inspire your life.