Newton's Third Law of Motion states: to every action there is an equal and opposite reaction.
If there were a Newton's Third Law of Productivity it would state: your actions will have consequences; do you know exactly what they are?
Productivity 4, Plan-Do-Review
Productivity 5. With Instant Comes Distraction
Productivity 6. Process vs. Content
Productivity 8: Match Energy & Resilience to Pay-Off
Productivity 9: White-board vs. Phone
Productivity 10: Search vs. Organise
Productivity 11: Get it Right First Time
Productivity 12: Occam's Razor of Productivity
Bonus: You, Only Better