Desiree, wishing joy for that stranger is a wonderful thing to wish for, and it's not my job as a service provider and technician to tell you how to use your wishes, but if I were you, I would think really hard.  Do I want to give the last wish I had, knowing that I already burned two without even thinking about it, on a stranger?  Now, I'm not saying you're right or wrong.  I'm just saying, think about it.
I understand.  It's just that I'm feeling this burden of responsibility.  I would like to feel a little bit easy-come-easy-go with these wishes and, because I already used two, why not just give up the last one?  I don't want it.  I don't need it.  I want this strange man to feel like his life is worth something.  I mean, for God's sake, he's a fencing instructor.