I honestly think the best fics for this pairing play with the fact that Vados is essentially a godlike being and Goku is… well, Goku. A plot that hooked me recently had Goku accidentally stumbling onto some Angel-level secret during a training trip with Whis. Vados is sent to deal with the 'security breach,' but instead of wiping his memory, she finds his naive, pure-hearted curiosity disarming. The emotional tension comes from her growing fascination with this mortal who has zero reverence for her station, and her internal conflict between duty and this strange, forbidden connection. She starts observing him in secret, maybe even subtly altering events to protect him from universal-level threats he's unaware of, which builds this incredible slow-burn angst. She's watching over a man who sees her as just another strong person to spar with, while she's grappling with emotions she shouldn't even possess.
Another layer I love is when the plot uses Goku's family. Maybe Chi-Chi senses something is off, not through jealousy, but through a mother's intuition that some cosmic force is paying too much attention to her husband. Goku remains blissfully, hilariously oblivious to the romantic undertones, which just makes Vados's quiet yearning more poignant. The real kicker is the inevitable moment of choice: when Vados has to decide between her neutral Angel principles and actively intervening in Goku's fate, potentially facing consequences from the Grand Priest. That's where the emotional payoff shreds me every time.