Who says? Are you a fortune teller? The only thing in life that you know you'll be glad you did before you do it is sex. As far as everything else is concerned, you have no idea if you'll be happy that you did anything until you do it. You're going to meet tons of miserable people every day of your life from college onward, and they each came to be SOBs in their own uniquely awful way. There are happy people in the world too, and most of them can't tell you how they got that way. What we're saying is, it could go either way; It's truly a toss-up.