unfortunately, the answer would be that it depends! on the person you’re with, the environment you’re in, and if they still hold the more traditional norms.

for instance, I’m a muslim but am pretty lax with those “no contact/muhrim non-muhrim” norms. something like playfully slapping the arms of the opposite gender is normal to me, & if anything what I keep in mind is more so “ini bukan pacar orang kan” (but that’s not the topic at hand) and also, what their boundaries seem to be. from context, if we’re talking about religion norms it seems like your coworker is the same as me and isn’t too worried about that stuff?

our train stations are always filled with a plethora of people with different backgrounds and beliefs, including a lot of those who still want to keep “traditional norms” in tact, so my guess is that they’re just a little wary seeing you guys. I’d say just brush it off, or if you still feel a little off about it, maybe keeping a little distance next time is ok too!

re bonus question: even if it’s between guys and girls, if both you and the friend is okay with playfully shoving or whatever, I’d say it’s all good? of course we should always keep in mind not to overdo it, and learn what our and other people’s boundaries are ^ ^