Serious Business/Newspaper Comics

In one Calvin and Hobbes strip, Calvin throws an enormous hissy fit after losing a game of checkers to Hobbes. When Hobbes points out that it's just a game, Calvin cheerfully replies: "I know! You should see how I act when I lose in real life!"
- Chewing gum is Serious Business in the Calvin and Hobbes universe. Calvin is an enthusiastic reader of a magazine called "Chewing" which is dedicated to it, and informs an incredulous Hobbes that as many as twelve such publications exist.
- So is a Snowball Fight.
- And he treats his snowman creations like modern art. Though he certainly puts more thought into them than most kids.
  - Considering that they come to life and try to kill him...
    - This is Calvin. Everything comes to life, and most of it tries to kill him.
The Far Side once had a Showdown At High Noon having ended in defeat for the older cowboy, treating it with all the gravity you'd expect... except it was at ping-pong.

Older gunslinger: Well, you won. Now every player in the world will come after you, looking to make a name for himself... Welcome to Hell, kid.

This Dilbert strip illustrates how to apply the principles of Serious Business in the workplace.
- This comic was based on one of Scott Adams' coworkers, who actually said "I will fight you to the end of the earth!" To him, it was serious business.
Board games are apparently serious business to Rat in Pearls Before Swine.