You must evaluate the overall situation, but never assume that one course of action - even if it seems the most likely - will be the correct one. If the ball is hit well to your right and the runner takes a considerable lead, for example, throwing to second base would not result in an out, whereas a throw to first base might.
Aviation radio communication works in the same way. A student will goof up a radio call and then say to the instructor, "But I thought he would tell us to make a right downwind entry." An assumption was made that resulted in confusion when an unanticipated instruction was issued.
Errors of assumption are also common during instrument flight. A pilot is approaching a familiar destination where he always receives the same arrival clearance. This time, however, a different clearance is issued, and he's caught off guard. He stumbles on the clearance readback, and because of the confusion, mistunes a navigation radio. The situation degrades because a wrong assumption was made.
I avoid this trap by keeping an open mind whenever variables exist, and I am always ready for the unexpected. Listen, think, and react. That's the best course of action, because you can't determine the best play until the ball is in your glove.
Worriment is another dangerous situation that's easy to illustrate. When I'm on the ground, snap decisions are not common. I usually have lots of time to think about my choices, discuss it with others in some cases, and make my decision.
This situation does not always exist when I'm flying. To survive in flying's dynamic environment, I must make quick decisions and move on to the next challenge.
The decisions I make are not always perfect, and when this occurs, particularly during a checkride, I don't worry about it. It's history. I know that I must quickly shift gears and concentrate on the next challenge.
I learned early in my flying career that if I worried about a previous decision or error or what an examiner might be thinking, I did not fully concentrate on the task at hand and my performance suffered. I have seen this happen time and time again to other pilots. It's like fixating on drift during a crosswind landing or on a specific problem during instrument flight. Everything else starts going down the drain.
I avoid this trap by maintaining the proper level of self-confidence, and this only occurs when I maintain the proper level of proficiency. If you are a private pilot, are you comfortable performing stalls and slow flight? Can you consistently make crosswind, short-field, and soft-field takeoffs and landings? Can you consistently fly a rectangular, right-traffic pattern at a strange airport? And, can you do all of this without concentrating on the flight instruments, as so many pilots tend to do?
If you are an instrument pilot, can you readily identify instrument failures? Can you fly the basic instrument maneuvers using partial panel for reference? Can you fly straight and level for a prolonged period and quickly determine the proper wind correction angle? Can you navigate and fly VOR and ILS approaches with just one VOR/ILS receiver? Can you determine estimated arrival times at fixes using rules of thumb instead of a calculator?
These actions require practice, and some pilots ignore this basic flight safety requirement. Consequently they fall into the trap of making assumptions or doing things that cause them to worry - definite indications that proper proficiency does not exist.