Now my big question ... I am using mini USB-serial breakout board, it works now but it doesn't make sense that I have wired Tx-Tx and Rx-Rx, instead I would have thought I would wire Tx-Rx and Rx-Tx, even though it works I am curiosu what I am missing from my electronics 101 limited knowledge
That is because in the serial world there is not agreed standard on if a given serial signal is an input signal or an output signal. A signal called TX is wired between two modules such that one side is an output signal and the other is an input signal, the same applied to a signal named Rx. But on any given module the name Tx or Rx doesn't tell you if it's an input pin or an output pin. The Atmel folks on their AVR chips defines the serial input pin as Rx and it's serial output pin as Tx. Your specific USB serial device is naming it's Tx signal as an input pin needing to be wired to a serial output pin, and it's named Rx signal is an output signal needing to be wired to a input pin.
So it can be confusing because of none standard naming convention, but basically it boils down to the electrical requirement rules, and output pin on one module must wire to a input pin on the other device for both serial signals. Wiring two output pins to each other can destroy either or both devices and wiring two input pins is not destructive but passed no information.
So it's easy to tell which pin is an input and output serial signal on a arduino because it's documented, pin 0 is an input pin and pin1 is an output pin, but one can't assume that any specific USB serial module uses the same naming, so you have to try and figure out from it's datasheet if a given serial pin on the module is an input pin or output pin regardless of what they name the pin.
That make sense?