My first shiny was a shiny Bidoof in Platinum (which I am not proud of... T_T). But before that, I had encountered a shiny Shinx, but being the negative person that I am, I predicted that whatever move I made on it would be a critical hit. And guess what? I used Tackle, it was a critical hit, and the Shinx fainted. u_u
Then after all that, I encountered a shiny Shellos. I was too scared to make any mistakes with using my more "powerful" moves, so I just used Tackle a bit, until its HP was yellow. I didn't think that was enough, so I used Tackle one more time... critical hit. (I'm sure you know what happened after that >.>)
So all I have so far is a shiny Bidoof and that shiny Gyarados from HeartGold. *sigh*
I REALLY wanted that shiny Shinx. =/