What's important to recognize is that Advantage/Disadvantage doesn't technically ban or even replace the diegetic conversation. In theory the two procedures can co-exist, but in practice—with player priorities, optimal play, and finite time—A/D takes precedence.

Niv Lova does include an encounter range table. The encounter might be very close, giving you little opportunity to hide. You might also see them from afar, giving you ample time to position yourself for an ambush or avoid the encounter entirely.

It is not a stable state because the “perfect” balancing point is dynamic – even a 4,000 year old game like Go still has had balance adjustments in the past twenty years.

Opening Stuck Doors. 2-in-6 -> STR check with disadvantage.

When players are attempting something that you have already determined will succeed, it can happen that circumstances suggest there could be a cost to it. For example, climbing a very difficult surface. The cost could be lost time (always a precious resource when you track time with the random encounter die), broken tools, exhaustion, injury, etc. Or the inverse - even faster than expected, went up real quiet, etc.

"Can I use Stealth to climb down the well?" "No," I said, "No, you may not. You can use a rope to climb down the well."

The DM gives another +2 for the handsome tip and decides 18 is good enough to make a good impression.

Actually a Persuasion roll

Doing something for loved ones can allay our anxiety about them