A key game mastering skill is metering the stakes properly. Stakes are simply what the characters can gain or what they can lose. The consequences of their actions. The ultimate stakes in a fantasy adventure game may not even be the characters’ own lives but the fate of the world or even the multiverse if you are playing in a high enough level game.
The situation dictates how much information I communicate to the players about what is at stake. This is particularly important if the encounter is a point of no return. If the players cross a boundary from which there is no return, then I am very clear with them about what their choice means. This is not a place I play, “Gotcha!” On the other hand, when the players can retreat or the consequence is minor, I talk in more vague terms; “possibly”, “probably”, “maybe”, “could be.” Then if they probe or ask further questions I will dribble out more information until they feel confident enough to make a decision.
I slowly escalate the stakes of an adventure or a site. If the players are traveling to an adventure site, their random encounters might be relatively minimal and easily defeated. It will involve a minor expenditure of time and resources. As the characters go deeper into the location, or the plots of their rivals; the stakes escalate until the players realize that they might have gotten in over their heads.
Encounters may be unbalanced. My current campaign running around 5th level at this point and the party can mow through a band of goblins so easily that we just hand wave it when it comes up on the random table. There are a few results on there that could be a total party wipe if they don’t parley or run. I personally like having encounters that are across the spectrum of easily defeated with violence to impossible to defeat with violence. It reminds the players of how far they have come and how far they might go. Some day, they might defeat a small war band of giants but not today.