"Boil things down to the most fundamental truths... and then reason up from there." First principles are like gravity: they work whether you believe in them or not.
Mimicking tier systems without understanding why they worked. Programs look good on paper but fail to deliver.
Treating partnerships as one-time exercises. What worked in year one becomes a liability in year three.
Focusing on revenue KPIs instead of structural problems. Adding tools rather than fixing fundamentals.