I joined several times, and it never won... maybe about fifteen to twenty times I guessed the Bitcoin price on a contest on the Bitcointalk forum... it was never right... it seems I'm really bad at predicting prices... LOL
Minimal analysis and very uneducated are probably the main causes, I really want to win even just once,,, but even that never happened... from there, some of the guesses I wrote were only based on instinct, because I had given up on this guessing analysis... yeah maybe if one day I get the right prediction, it means it's just my luck... because a winrate below 8% is very bad.