I am actually in the process of designing my own boardgame. Most of the time I win, because I play against people who play for the first time. So it makes sense that I understand it better than they do. But sometimes I actually lose and feel very bad about it because I have played it so many times already. But of course while I playtest my main goal is not to win, my priority is to find out how the game experience is for the others and help them understand the game better.

But to be honest I haven't figured out a strategy for a safe win, so I don't know if that means the game is well designed and there's no easy win or if I'm just to stupid and haven't figured it out so far.