Well, until now, I have caught three pokemon without master balls. So one of them, which was the first one, was Suicine. I was playing HeartGold when he appeared infront of me. He was low on health, as I took him down the last time we met. I had one pokeball left, and I slowly picked the pokeball, as I was so hyped. Every time the pokeball shook, I gasped. I was just so happy to catch it.
The two other ones were pretty meh. I was playing White 2 and I found Virizion. I fought him, and simply fought it with my Unefezant, then I simply caught it with a net ball that I picked up earlier. that was pretty meh.
The third one was Yvetal. I mean, I was pretty happy when I caught it with a quick ball, but I wasn't as hyped as the Suicine one. It was still way better than Vrizion, which was really boring.