Murphy's Law vs Sod's Law
Murphy's Law and Sod's Law are close relatives. Both describe the feeling that failure arrives at exactly the wrong time, but they come from different traditions.
Murphy's Law
Murphy's Law is usually phrased as: anything that can go wrong, will go wrong. Its origin is tied to engineering and defensive design.
Sod's Law
Sod's Law is the British cousin: if something can go wrong for an unlucky person, it probably will. It leans more into timing, irritation, and everyday unfairness.
The practical difference
Use Murphy's Law when you are designing systems. Use Sod's Law when you are explaining why the train is late, the printer is jammed, and the deadline is today.