This is a question we have to answer ourselves when we travel. And the real question should be, is it going to make me a better person? Travelling since the beginning of time was religious or illness related, but it always meant to make us better.
So before you put yourself on a plane, a train or a ship take some time and think about this. What are you really looking for? What do you want to take home with you that you didn't have before?
Don't come just to get away. Come to be a better person than you are now.
Don't come just to get away or see something different. Come to Lisbon — or anywhere else in the world — to be a better person than you are now. If you're open to that, you'll get far more out of six hours walking this city than any highlight reel could give you.