Motivated to get to the beer tent before the beer runs out. You finish worse than 15th in a Cat. 4 race, you need a beer but can't get one 'cause the kegs dry.
Hmm first thing that comes to mind is to stay faster than my wife.
In all honesty much of my improvement in skills are based on learning in order to help her improve as a rider. I was pretty content being a mediocre cat3 when she started racing and I the needed break things down into teachable steps it forced me to analyze what I was doing and thus become a better rider. These days when she gets a coaching session I will also go along so I understand all the elements she has been taught for training practices later.