I was testing the redstone wires changes with 2 pistons and discovered that if you spam-click a lever closer to the first piston it sometimes powers the further piston instead. 

What I expected to happen was...:
The piston closer to the lever always powered first

What actually happened was...:
The piston further to the lever sometimes powers first

Steps to Reproduce:
1. Place down 2 piston like I did in the attachment

2. Connect both with a redstone wire

3. Place a lever closer to one of the 2 pistons

4. Spam click the lever