Good vs Bad Tension
The way in which tension is created will greatly influence how it actually feels and whether it actually leads to engagement or not. Tension that goes wrong and does not lead to engagement is categorized as "bad tension".
Bad TensionBad tension occurs when the stakes and/or anticipation are either too high or too low (see the chart to the right). If the stakes and anticipation are not at least somewhat balanced, engagement will also be less likely to occur. High stakes with little anticipation rarely feels satisfying (the anticipation is too low), while building up lots of anticipation for something with low stakes will feel like a let-down (the stakes are too low). The greater the imbalance between stakes and anticipation, the more difficult it will be to drive engagement. It can be done in some cases with some people, but it takes a lot of skill and usually should be avoided.
If either the stakes or the anticipation are too high, then tension will be too much and will overload the audience, and engagement will decrease instead of increase. When an individual gets to about a 9 on their personal tension scale, they are usually right on the edge of what they can handle, which can be very engaging. However, at a 10, the tension is too much and they begin to shut down and start to disengage from the experience (the tension is rapidly turning from good tension to bad tension). There is still some engagement, but it is dropping fast. Above a 10, the tension is complete overload and they completely disengage from the experience. This effect is called "tension overload".
Some examples of situations that are usually perceived as bad tension are: arbitrary punishments, complete loss of progress, forced choices that are inconsistent with the plot or characters, deus ex machina moments in a story, multiple reversals, generally disjointed storytelling, feelings of helplessness, arbitrary rewards that feel unearned, generic or disappointing rewards, uninteresting choices, loss of autonomy at important moments, easy challenges that were built up to be much more difficult than they are, etc. When done very skillfully, these examples could still be engaging, but it is very difficult to keep the stakes and anticipation balanced in these situations, so they should generally be avoided.
Tension LimitsEvery person has a different limit for the amount of tension they can handle. The chart to the right shows a possible set of limits for hard core, normal, and casual audiences. Trying to create a highly engaging experience for all three of these audiences is very difficult (and often the right answer is to just focus on a single audience), since the level of tension that would be highly engaging for someone who is hardcore would overload someone who is casual (and a low level of tension would be boring for the hard core audience). In an interactive experience, allowing the audience to control the level of tension they want (through difficulty levels, player control of pacing, dynamic difficulty systems, etc.) can help with this problem.
There is also a limit to how much tension an individual can handle over time. Even with valleys in-between the peaks of tension, eventually the total accumulated tension will be too much and that individual's tension limits will start to decrease (sometimes very rapidly). This means that tension that was fine just a few minutes ago might now cause tension overload. This effect is called "tension burnout". If the nature of the tension changes, this can help prevent burnout. For example, a person who has experienced high tension all day in their job might want to experience a completely different type of tension by playing a game when they get home. Within a given experience, switching between engagement types is a good way to prevent (or at least delay) burnout.
Eventually, though, no amount of change in the nature of the experience will help and burnout will occur. This is why someone might seek out a low engagement experience on purpose; the low engagement experience will have low tension, which is exactly what they want. Once they have recovered enough and are no longer feeling burned out, they will be ready for a high engagement/high tension experience again. Within an interactive experience, if it is a very long one (large RPGs, MMOs, etc.), it is usually wise to have a good number of optional low tension activities to allow burnout recovery to occur while still being in the experience.
Individuals' thresholds for overload and burnout vary wildly, and even vary in the same individual based on the nature of the tension. In particular, individuals' thresholds for tension caused by negative stakes tend to be much lower than that caused by positive stakes, and thresholds tend to be even lower if those negative stakes are part of an interactive experience. This not true for everyone, but is so common that it must be accounted for when creating a commercial experience for a large audience. A designer must always keep this individual variety in mind, as there is no one perfect way to handle avoiding overload and burnout. In general, a designer must find the right mix that works best for the largest number of people in their target audience.