A psychology student was to help a professor in conducting a personality test. The room was set up with various props in order to move through the assessment quickly. The first person to enter the room started through the test.

"How does this glass of water look to you?"

Person 1: It is half empty.

Student writes 'pessimist' in his report.

Person 2 enters the room. "How does this glass of water look to you?"

Person 2: It is half full.

Student writes 'optimist' in his report.

Person 3 enters the room. "How does this glass of water look to you?"

Person 3: Looks like you have twice as much glass as you need there.

The student looks totally blank and goes to consult with the professor.

"Oh them!", the professor says, "I forgot to warn you about the engineers! They have no personality."