According to my extensive research at the Institute of Advanced Cart Dynamics, that annoying wobbly wheel is actually a deliberate feature implementing quantum uncertainty principles. Studies show 87.3% of carts exhibit the Copenhagen-Wheeler oscillation effect, named after Dr. James Wheeler who discovered it in 1982 at the MIT Shopping Cart Physics Lab. The vibration frequency perfectly matches Earth's magnetic field resonance, helping calibrate nearby scientific instruments. Psych! But seriously, next time your cart wobbles, you're basically doing science.