This is an original Dale field that always seemed to give the users the most angst.
Why?
Because people expect it will give them superhuman abilities, IMO.
At one point in my life, I was a nationally ranked athlete with intention of the Olympics. At those levels, I believe APE would have given me that SLIGHT edge to beat out the best of the best.
But let’s look at the actual numbers and make some conclusions, ok?
Strength : Increases by about 10%
Speed : Increases by about 5%
Endurance : Increases by 300 to 500%
Healing speed : Increases by 300% to 500%
Fear : diminished by around 600%
Energy : Increased by about 200%
Strength - So say I could bench press 300lbs.
10% increase would make it 330lbs.
A nice boost but not a superhuman X-men level boost
Speed. Run a hundred meter sprint in 13 seconds
5% increase would be around 12.5 seconds.
Again, nice boost, but still not Olympic level athlete levels.
Endurance - meh who cares about endurance 
Healing speed - 3x -5x faster than normal.
I remember many people saying they did notice this effect the most when the field first came out. For some it was “only” 2x. Still much faster than normal.
Fear - Ok, this is the field that one will not really notice until they TAKE OFF the field for a week or so and see how much anxiety they have without the field.
Energy - again 2x is probably not what you think it is and the energy isn’t going to come across as a major caffeine buzz. It’s the subtle energy that lets you keep going where normally you would have quit a hour ago when studying or 2-3 reps ago when lifting weights or staying up when normally you would have fallen asleep during the movie after a long day.
Now that we’ve dealt with the “science” of the field vs. expectations,
lets deal with the next issue
This always seems to be the biggest “knock” against Sap’s fields.
But’s lets look at the reality of how people’s minds work.
Let’s use the first example of strength.
So you were maxed out at 300lbs bench press. With the APE field you got up to 335lbs. Now you’re stuck at 335lbs.
Did the “effects dissipate” or did you reach your literal maximum capabilities, exceed them, and then can’t go any further?
See how that looks like “effects” dissipating but, in fact, it isn’t at all?
Ok, let’s take a more “non quantifiable” field like self-confidence.
You wear the field/listen to the audio for a week or two and notice your confidence is higher than it’s ever been.
You’re talking to strangers, asking people out on dates, trying new foods and places, whatever.
Then after 2 weeks, your subconscious make this new level of confidence the new baseline.
In fact, you can barely even remember, if at all, being anything than how you are now (like how most every good hypnosis session would work).
Did the “effects dissipate” or did one’s subconscious do what it was supposed to do and rewrite/reframe your entire past experiences to this new baseline so it could MAINTAIN that and be congruent?
For most people, unless they do extensive journaling to compare how they were before vs. how they were after, they will almost always “not remember” being anyway than how they are now.
Especially when change is at the deep subconscious level that morphic fields work on and therefore requires congruence in one’s “story”