This is a great question and great to see the different responses. I think the differences in answers stem from our experiences, our surroundings, our fish available to us and the stage we are in in our flyfishing journey. I read an excellent article on that sometime back... and actually managed to find it first time! 2010 September The Fishing Gene
For me I crave big fish right now... I want to tussle with the heavy weights around... be it pike, trout or carp or whatever else is around... I have caught some decent fish in my life so far, but after my first season in Canada where I have been exploring a new countryside my motivation has been fueled by a desire to catch big fish. I relish the opportunity to take on the challenge and solve the puzzle and experience the reward.
It will be a while before I can take my rod in my hand again, but when I do, I want to be ready! I can handle getting skunked for the simple reason that being outdoors is a reward in itself, but I am prepared to go to just about any length to find those photo worthy fish, the fish that I can get a picture of, even maybe a replica mount, so that years from now, when I have kids/grandkids and they ask me about that pic/mount I will be able to sit them down and tell them a real good story.
I used to fish competitively for a number of years back in South Africa and it got to the point where I was sick of catching small fish in numbers... while I am no longer sick of that and when the days of getting skunked get to me I know where to go where I can get my fill of setting the hook 30-40 times a day... but when I am left on my own, for any length of time, I plot and I plan and I dream of those fish... I have set myself some goals, and they drive me... They are: a 10lb Rainbow, a 20lb Northern Pike and a 30lb Carp... Once I have met those goals I'll re-evaluate...