I tend to be a "seen but not heard" person. And from my perspective, it's perfectly normal to let the superior talk, while I stay put. I feel it's showing respect.
It's a matter of internalized culturally-specific social
hierarchical etiquette (and patriarchy, and misogyny, and a bunch of other things I've been immersed in growing up), as much as the more
personal matters like lack of confidence and a lifetime of self-esteem
issues and a fear of talking to strangers, amongst a basket and a half of other issues.
I'm still very much bound by traditional values and social mores. Maybe even more so, because I'm away from home - everything I've been learning and internalizing thus far is up on the surface.
It's been brought to my attention that I tend to be not-so audible with goodbyes. I bow. That's because of the above reason. As much as I know it's not at all disrespectful (here or in Japan, most of the time), I feel very reluctant to speak to anyone senior/superior. Especially if it's not my friend but my boss's (ergo an automatic senior/superior), I feel it's not my place to speak, even a goodbye. A bow is sufficient, or so I feel in a part of my brain.
It also means I don't have to talk to people, which saves me from accidentally being disrespectful, or any type of potential conflict/threat.
I think it was implied that maybe I'm being disrespectful to these people by not saying goodbye, or speaking aloud. It was a bit of a shocker.
What counts as respect/courtesy is different between what I (believe) is the norm back home, and what it is here. It's a very common experience (clashes between two cultural perspectives), but it's still a very ambivalent and difficult situation nonetheless, and I feel at a loss. Even more so recently, when I have more situations where I need to talk to people who I don't know.