The TV-series Criminal Minds usually has a quote at the begin and end of each episode. Of course they are somehow fitting to the episode and some of them are quite nice. I found one that I like pretty much:
“We must be willing to let go of the life we planned so as to have the life that is waiting for us.” ― Joseph Campbell
I think this one is also a quite important one. It makes no sense to plan everything in life, your plan may get turned upside down. I think, nevertheless, you should have some goals. You can of course specify them a bit, but you shouldn’t formulate them too strictly and allow them to chance, if you get another opportunity you haven’t thought about before.