Permanent link to this comic: https://xkcd.com/103/
Image URL (for hotlinking/embedding): https://imgs.xkcd.com/comics/moral_relativity.jpg
[[A graph, rationalization as a function of speed, increasing exponentially with an asymptote at c]]
Related to moral relativism, it states that ethics become subjective only when you approach the speed of light. That is, it's okay to be self-serving, steal, and murder as long as you're going really, really fast.
(Note: This is why rap sounds better on the highway at 90 mph)