With a well applied joint lock there is no such thing as failure
The very nature of joint locks is all or nothing - they either get the submission or they don’t - sometimes the dividing line is very narrow indeed. It is important that you don’t let this fact permeate into your thinking in a way that becomes destructive to your performance. While it’s true that the obvious outcome of a joint lock is black or white - submission or not; there are other important benefits that come from a well applied joint lock that occur even when you don’t get the submission. First, Sometimes your opponent simply refuses to tap. In these cases, continue the break and now his performance will begin to drop as the injury takes effect, leading to other routes to victory. Second, a threatening lock will elicit strong defensive reactions that enable you to go forward in other ways - towards a reversal, a new position, another submission hold etc. so that even failed joint locks can have excellent consequences if sufficiently threatening. Third, your opponent will now be much more respectful of your skills once he has felt serious danger and hence much easier to manage as the match progresses. These and other benefits of such joint lock attacks that don’t actually get a submission raise an important point - EVEN WHEN A POWERFUL JOINT LOCK ATTACK FAILS, THERE WILL BE TANGIBLE BENEFITS FOR YOU TO TAKE ADVANTAGE OF. Don’t get dispirited if you don’t get the tap - instead, TRAIN YOURSELF TO LOOK FOR THE POSITIVE OPPORTUNITIES THAT ALMOST ALWAYS ARISE FROM THOSE ATTACKS AND SCORE WITH THEM. Here, Gordon Ryan comes close with a powerful heel hook attempt in a very close match - the lock ultimately failed insofar as it did not get the submission, but it forced a strong defensive reaction that under the rules of that particular match, scored the match winning points. Don’t concern yourself with the outcome of your joint locks - that’s up to your opponent - concern yourself with generating maximum breaking power and then a good follow up that takes you forward should it not end the match.