I believe this is the question that a user was trying to get at here. Geas states that you cast the spell on a creature, thereby
forcing it to carry out some service or refrain from some action or course of activity as you decide.
The use of the word "forcing" would seem to imply the creature has no choice but to carry out the action you demand of it. However, the spell further describes
While the creature is charmed by you, it takes 5d10 psychic damage each time it acts in a manner directly counter to your instructions, but no more than once each day.
This makes no sense unless it is possible for the creature to disobey you. If the creature has the option to disobey you, then the word "forced" is inaccurate. Should we therefore dismiss the first sentence of this spell as (inaccurate) fluff? Can we safely assume that the creature is not forced at all, but rather coerced into service by the threat of 5d10 psychic damage (which may be an empty threat against creatures with sufficient hit points)?
Best Answer
The spell works by coercion. As it says, those who act contrary to the geas suffer damage.
There's no need to introduce a fluff/crunch dichotomy here to resolve this either. The normal word "force" adequately includes coercive force, so there is no contradiction. Taken as a whole, the spell forces obedience.
The possibility of ignoring the damage and taking it on the chin is certainly possible. For a character with fewer than 51 hit points it is potentially or easily fatal, and therefore unlikely. For someone with more, it becomes a significant handicap, since with the bounded accuracy of 5e, hit point are a large part of what separates a higher-level character's effectiveness from that of a lower-level character. Defying a geas every day is certainly possible then, but would be a heroic act of stubborn will and not done lightly. Since resistance against force does not make the force non-existent and in fact emphasises its influence, there is again no contradiction.