With Icelanta on this.
Its all well and good being a whiz with the FMC, what happens that fateful day you lose it.
Below FL100, the last thing you want is the airplane happily flying downhill at 250 kts and your head is in the box.
The is a lot more to flying than constantly playing with the bloody computer.
Situational Awareness, is knowing where you are in space and time, not following a bloody magenta line without question.
Paulm1949, you will find the green banana will help a lot more than finger tapping the FMC, the VNAV can catch you out if you over rely on it.