Sheldon famously declares 73 the "best number". It is the 21st prime number. Its mirror (37) is the 12th prime. In binary, it's a palindrome: 1001001 .
Fans often point out that Sheldon and Amy eat lunch in the lab while Amy is slicing brain tissue—a major violation of safety protocols.
After rejecting Zack's lack of intellect, Amy adopts the Vulcan practice of Kolinahr to purge her emotions. [S4E10] The Alien Parasite Hypothesis
Dismissed by Amy (despite Sheldon's "testy bark of an old biddy" comment).
Amy attempts to satisfy her urges by approaching Zack, telling him she is "130 pounds of raging estrogen" longing to "make Shakespeare's metaphorical Beast with Two Backs". Sheldon famously declares 73 the "best number"
The "cold, harsh truth" they eventually accept. Iconic Moments & Quotes
Sheldon’s preferred theory, as he finds it more plausible than the final option. In binary, it's a palindrome: 1001001
In The Big Bang Theory Season 4, Episode 10, Sheldon and Amy's relationship faces its first biological "crisis." After Amy experiences a physical reaction to Penny's ex-boyfriend Zack, she and Sheldon attempt to diagnose her symptoms with rigorous scientific logic. The "Diagnosis" Breakdown