The ump apparently doen't watch as much TV as you do and wasn't aware of this common "ritual."
It sounds like the umpire mistook your tapping of the outside of the plate as a demonstration that you were unhappy with his call. When he asked you if you were arguing balls and strikes, you should have told him that this was your ritual. As annoying as rituals can be, unless they unduly delay the game, there is really nothing wrong with them.
Rituals that are performed before an at-bat are not as near annoying as a ritual that needs to be performed before every pitch.
If they last too long I just let the pitcher send the message that the batter is taking too long to get ready.