Ground Planes Make Much More Sense to Me Now

I used to think ground was just another connection.

After reading more about signal integrity, I realized it's actually the return path for high-speed signals.

That changed the way I look at PCB layouts.

Instead of focusing only on signal traces, I now pay much more attention to maintaining a continuous ground plane underneath them.

Sometimes improving the ground layout solves problems that changing components never could.

I'm curious—what was your biggest "aha" moment when learning PCB design?