That is an experience I've been through often. It has happened to me on a frequent basis in Crystal, Ruby and Diamond. Usually, I'd have been training a pokemon to level 100 for the sake of having it at said level, and days later, I'd find myself not knowing how I was going to go about the situation, (finish or lose) wondering whether I'm forgetting something or not when I go ahead from checking where I've started, and thinking is it more worthwhile to train or to go onto whatever it was I turned the game on for.
I haven't been on my current game for a long while now, therefore having no memory of my last actions, but 8 times out of 10, I'm usually gonna be looking at Aaron, Bertha, Flint or Lucien. I wouldn't bet against myself being there right now if it weren't for the fact I know I've had a look at IV training. Nevertheless, though, it is a self-inflicted annoyance I think of when hearing the slightest mention of pokemon.