Well, actually, we weren't always mortal enemies. Instead, when we were much younger, say, in Primary 1 or 2, we were quite close friends. I would either go to his house to play or he come to my house to play after school. He would play with his mom's phone, and I would watch him. He was quite a nice person. WAS. (He's actually pretty dirty-minded now, really.)
Also, when we weren't in our houses, we'd play catch at the void deck under the HDB flats with some of my other friends. I admit that it was quite fun. I hated it when I was the catcher, though. My neighbour was always too fast for me.