Tip the waitress/waiter?

I personally agree with leaving a too for the person that serves you at restaurants because you never know, you might just make their day even better. You do not know why they have the job in the first place. They could be struggling to make ends meet and being a waitress/waiter might be the only job they can get. They might be working their way through college and need the extra money.
So don't cuss at your person waiting on you,just leave then a tip or some kind of nice note.it might lift their spirits...