on Writers Helping Writers:

Realistic, evocative dialogue is an important part of any successful story. We need our characters’ interactions to be authentic, consistent, and engaging to draw readers in to what’s happening. So when we’re learning to write, we spend a lot of time on mechanics—learning all the grammar and punctuation rules. But proper form is just the first step.

When writing strong dialogue, we often forget that real-life conversations are rarely straightforward. On the surface, it may seem we’re engaging in simple back-and-forth, but if you look deeper, to some degree our conversations are carefully constructed. We hide our emotions, withhold information, dance around what we really mean, avoid certain topics, downplay shortcomings, or emphasize strengths—all of which leads to exchanges that aren’t totally honest.

Completely candid dialogue scenes fall flat because that’s not the way people converse.