It's like drugs. Quick burst of happiness with minimal effort. But you get used to drugs, and need more and more of them to replicate the same sensation you got the first time. When you finally break your addiction, none of the happiness remains. You can't think back fondly on the time you procrastinated and surfed reddit for hours instead of studying for an exam. You're not a better person because you learned that Cleopatra lived closer to our time then the time when the pyramids were built.

If you get away from reddit and start pursuing real life hobbies, socializing or experience new things, you get long-term happiness. Accomplishments you can be proud of, better health, better quality of life, friends, unique and interesting memories. If you run a marathon, the happiness doesn't just disappear afterwards. You can remember the accomplishment and the unique experiences you had along the way and feel good about yourself.