If it weren't for the coffee, I’d have no identifiable personality whatsoever.

Framed as self-deprecating humor, the line treats coffee not merely as a stimulant but as a prop for identity—suggesting that without a daily ritual and its chemical lift, the speaker’s “personality” would be indistinct. The exaggeration is the joke: it satirizes modern dependence on caffeine and the way people narrate their habits as essential traits (“I’m nothing before my coffee”). In a Letterman-like comedic register, it also pokes fun at the constructed nature of a public persona, implying that what audiences read as temperament or charisma may be partly routine, fatigue management, and performance rather than some stable inner essence.