I havent BOUGHT sunglasses in 25 years+. Always steal my older brothers...
I took a pair of his sunglasses when I was like 15 years old, and he never realized it, and he even commented later that he was looking for his sunglasses and they looked kind of like mine (his) but they were different.
It was funny to me, and then years later he left a pair at my apartment. I decided it was my fate to have my sunglasses supplied to me by my brother.
He doesn't know of this at all, and I am not a horrible brother... I buy him gifts all the time just to be nice. Its more of an inside Joke that I have decided to let him in on when we are old men. I think he will laugh.
You might think this is an asshole move, but you'd have to know our relationship to know it's not. He wouldn't be mad... so I just have decided to keep this going for the next 20-30 years.