49. There are few tangible rewards.

When you build a house, paint a painting, bake a cake, or clean a room, you can step back and see what you have accomplished. Whether you work alone or in a team, being able to contemplate the finished product of your labors is a satisfying experience, a reward for your work. When that labor is further rewarded by a paycheck, it is all the more satisfying. Many modern occupations come with few tangible rewards but at least provide an income. Graduate school offers little in the way of either.

Instead of being able to see the work of your hands or the product of your ideas, you can reflect upon the thousands of hours that you spent reading in preparation for your exams, and how quickly the impractical things that you learned in the process slipped from your mind the moment that you completed them. You can meditate on the hundreds of thousands of keystrokes that produced the tens of thousands of words that you typed while staring at an ephemeral image on a screen. After a few years in graduate school, you can print out hundreds of pages of text that you have produced, but looking at a neatly-stacked pile of paper is hardly inspiring. (Would your writing inspire anyone who reads it?) After several years, when you are finally handed a piece of paper in recognition of your efforts, you can step back and contemplate your empty bank account.