CAP theorem
The CAP theorem is the whisper of a sorcerer on the stage of distributed systems, proclaiming that the three ideals of consistency, availability, and partition tolerance cannot all be seized at once. Implementers wield this doctrine as a shield to create design compromises, and operators glorify their operating pains as acts of wisdom. The only truth is the cruel mirror reflecting that some sacrifice will inevitably occur. Those who call this sacrifice a "necessary trade-off" are true believers in distributed systems.