How do you feel when your tefillin are borrowed?

How do you feel when your tefillin are borrowed? I've just arrived at Shachrit, they don't seem to be anywhere and it's a pretty sure bet some visitor, or some regular who forgot his, has borrowed mine. And they borrowed mine because there isn't any extra pair left for me. I can smile and say "You're welcome" at the end of services, but meanwhile there's nothing much to think about except, "Why was I late????"