Dice

1. Uncertainty
When firing an arrow, it bends around the frame of the bow as it is loosed. It wobbles and wavers on the way to its target, giving a greater and greater area of where it might land the further it travels. There has never been any bow so well known, or any set of arrows that so perfectly crafted, whether from ancient or futuristic materials, that this disappears.

There is chaos in the system.
It may be understood as percentages.
We reproduce it with dice.

If a skilled climber looks upon the ragged edge of a cliff face, is any of the route beyond what they can see and plan for as they look up at it? Is there any risk of the surface of the wall coming loose?
Are they weak or slowed or carrying too much or injured from fighting? If not, they simply climb the wall and get to the top.
If there are some minor hindrances, but nothing major, let them know and have them roll against their climb skill to see if they make it in one turn or two.

If dice reproduce uncertainty, then rolling them states clearly that something beyond the character's control is happening.
Whatever they were focusing on previously, they will likely stop doing so and start paying close attention to this.
If there's real risk or danger, this is a good thing.
But if there isn't something actually there to find or understand, trying to will be confusing at best.

2. Probability
Skill checks are rolled on a d6, which means a level 1 skill will succeed about 17% of the time.

3. Result
Considering the uncertainty and the probability above, determine what failure would look like and tell the player before they make the roll.