Basically what I'm looking for is when a character is given easy instructions on what to do where most people would probably succeed. However, the character who is given the instructions still somehow fails, and this is what causes a lot more problems than there would have been if the character had just followed the simple instructions.
Non-specific example: There are 2 buttons. Green button = good, red button = bad. The character is told this, maybe with the emphasis on the red button being bad. Yet they still end up mixing up the two buttons and pressing the red button instead of the green one, and now a disaster is happening because of that.
Alternatively, what about when a character is told that they should never, under any circumstances, do a certain thing (such as press the red button), which naturally leads to the character doing that exact thing 5 minutes later?