Average
Explanation
The Joke
A person asks God, "Are you good or evil?" God replies that on average, he is "very slightly good." The person is initially pleased, but God then shows a graph of his behavior over time. The graph reveals extreme spikes — God oscillates between being incredibly good and horrifyingly terrible, with the slight positive average only emerging from the aggregate.
God explains that his goodness is not consistent: he might be wonderful on some occasions but murderous during others, such as during a conference or in the middle of the night. A naturally good God would be uniformly pleasant, but averaging God includes extreme outliers — including episodes where he kills people and makes entire species go extinct in minutes.
The Humor
The joke uses the mathematical concept of "average" to reveal how misleading summary statistics can be. A being that is "very slightly good on average" sounds reassuring, but when you look at the distribution, you discover wild variance — periods of divine benevolence interrupted by catastrophic bursts of evil. The average conceals the extremes.
This is a satirical take on the problem of evil (theodicy). If God is good, why do terrible things happen? The comic's answer is that God is only good on average, and that average smooths over the terrible spikes. It also parodies how people use statistics to make things sound better than they are — "on average" can hide a multitude of sins, quite literally in this case.
Broader Context
Weinersmith frequently combines theology with mathematics and statistics. This comic is a particularly clever fusion, using data visualization (the graph with spikes) to illustrate a philosophical argument. The "misleading averages" concept is a staple of statistical literacy discussions, and applying it to God's moral character is a quintessentially SMBC move.