The truth costs a little now. A lie costs a little forever.

An honest answer takes one uncomfortable moment and then it is finished. A false one has no end date, because it has to be maintained, remembered, and protected from every future conversation that might touch it. The first price is larger on the day and much smaller in total.

When you catch yourself preparing a smoother version, say the plain one and let it be awkward for a minute. If you have already told a small one, correct it early, while it is still cheap. Notice how much attention gets freed by not having to keep track.