Age 2: No!
Meaning: I just figured out that I can disagree with you! Now I'm going to do it for fun, all the time!
Age 3: No!
Meaning: Don't tell me what to do, even though what you're saying makes perfect sense! I obviously have a better idea!
Age 4: No!
Meaning: Not only do I disagree with you, but I'm going to spend as much time as it takes to get you over to my side. You are clearly mistaken.
Age 32 (Me)
Meaning: I'm right, you're wrong! The end!