The Trick My Co-worker Played on Me

This post isn't about a customer, but my crazy co-worker at my night job who's name I promised not to use. My co-worker... 'Matt' is a really nice Fillipino immigrant. He's 2-3 years older than me and has 'adopted' me as his new American little sister. We tend to get side tracked alot with random conversations, but he works hard and still helps me finish my work.
I have pretty crappy eyesight. About a month ago, I forgot my glasses at work so I called the store to make sure they were there and went in the next day to get them. I picked up a pair that looked almost identical to mine, but didn't notice they were just plain black. Mine have some dragonfly designs on the side. It took me a few days to notice the difference since I don't constantly need my glasses.
I thought I had picked up someone elses glasses by mistake and looked for mine at work that night but couldn't find them anywhere. I asked one of my supervisors if they had seen a pair of glasses, they said no and if they were behind the counter the store manager hates clutter and had probably thrown them out. I had just got these a few weeks before and was devestated at the thought of them just being tossed in the trash and I felt bad thinking I had taken someone elses glasses now intentionally to replace my own. I was going to leave the 'other' pair for their owner but my supervisor said they would probably just get thrown out and to hold on to them and she would let me know if anyone else was missing their glasses.
A month goes by and my co-worker and I started talking about the glasses, he said "how much do you want to bet those aren't your glasses" At this point I had accepted and really believed mine were long gone. He took my glasses and peeled some black tape off the sides, my dragon flies showing again! He said he hadn't known at the time who they belonged to and was just bored, messing around.
If it had been anyone else in the world I would have killed them, for making me think I had lost mine, and guilty about supposedly taking someone elses, but I'm incapable of getting angry at him because he's such a nice guy. I was just relieved to have them back and realize I had them the whole time.
So word of advice, make sure you keep an eye on your personal belongings at work so you don't have to go through something like that.
Also I wanted to take a picture of my glasses to show the design on the sides, but I forgot them at my dads house a few days ago..