Theory of Constraints: A system is only as strong as its weakest point. Focus on the bottleneck. Counterintuitively, if you break down the entire system and optimize each component individually, you’ll lower the effectiveness of the system. Optimize the entire system instead.
The Second Law of Thermodynamics: The world tends towards disorder. That’s why your room becomes messier and messier over time.
Baker’s Dozen: The key to good hospitality is to delight your guests with an unexpected gift. If you run a hotel, leave a chocolate on the bed. If you run a bakery, give your customers one extra bagel. If you write a tweetstorm, share an extra idea.