"Ouch"

 And as soon as they realize I wasn't joking:

"Oh my gosh, did I hurt you?! Oh I'm so sorry, oh no. I didn't mean to oh I forgot oh no I'm so sorry!"

It's okay. Really. It's not like your friendly slap on my shoulder is a stab wound. Yes, it stung a little. Yes, what normally doesn't hurt your other friends or even my other arm did hurt a little. But I will survive. I have lived almost 18 years with this shoulder and I'm even tougher than you think. "Ouch" is a reflex reaction. The unnecessary pain still surprises me sometimes, but a second later I have recovered.

This tends to happen a lot. It's definitely one of many responses to my saying "ouch" after someone's friendly push or punch to my arm, but I've found it's the one made by those that care about me the most. The people I don't know very well get uncomfortable and quiet, and the people I don't particularly want to spend time with tend to just laugh. These are very broad generalizations obviously. The situations are very different and so spark different reactions from different people in different moments.

The point is, I hate these situations as much as the friend. I don't want you to feel bad! I am fine. I nearly always regret saying "ouch" even as it is leaving my mouth. I promise my arm is not about to fall off. You do not need to rush me to the emergency room and you definitely should not beat yourself up about making me say "ouch." I hurt perfectly healthy people with my friendly pushes all the time and that justifies feeling bad. This is not the same. I cannot expect you to, nor do I even want you to always be conscious of my shoulder's sensitivity and limitations. I'm just a normal human being who wants you to punch my right arm instead of my left.