The eternal battle between mathematical rigor and intuition!
Top: Real analysis students screaming about epsilon-delta proofs, formal definitions, and mathematical rigor that would make Cauchy proud. The formal definition (which is basically saying "for any tiny error margin ε, I can find a distance δ where the function values stay within that error") is their security blanket.
Bottom: Meanwhile, precalculus students living their best lives with the "pen lift test" - if you can draw it without picking up your pen, it's continuous! No fancy symbols required.
The gap between these approaches is why mathematicians drink coffee by the gallon. One day you're happily drawing curves, the next you're having nightmares about infinitesimals!
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