I was reminded of this recently while training Judo. We were told that during randori we need to go to throws with the intention of completing them. The way we spar in randori should be the way we will fight in competition: The body 'remembers' the throws and will perform them the same way in competition as in training. Once again, I was convinced of the importance of insisting: My stand up is nowhere near as good as my ground game and I find I hestitate when I'm going for a takedown, stopping halfway through the entry to a throw as if I don't believe in it and then turning out again. This has translated itself to be a problem for me at the last few competitions I've taken part in.
I am convinced that I should be able to integrate my judo training into my BJJ game, having seen other Jiu-Jitsu fighters implement Judo throws to great effect. While I'm still relatively inexperienced, I believe that a large part of the problem I have had using my Judo in BJJ competitions is psychological. My resolution for Judo, as it was for BJJ, is to insist; to believe in myself and never stop until I've put my opponent down.