I often find that the hardest part is finding the answer to:

Do you know what your long-term and medium-term goals are?

I honestly have no idea. I can easily focus on short term goals, when I am rather confident that Me(now) will be very similar to Me(goal reached). Things get harder and blurrier when I have to take into account my most likely self modification. Concrete example. Since I was 10, I've always wanted to be a physicist. Roughly near the end of my Ph.D. I started to evolve into someone who doesn't want to be a phisicist. I tried a short post-doc abroad and looked for a different job. If I had known in advance I could have spared me at least a couple unpleasant months abroad and a couple (make it 3) of years of underpaid work. But I didn't know. Now I find myself wanting to make a lot more money, but I keep wondering what will happen if this desire faded away abruptly and I finded myself trapped in an awful job.