MacBook Pro

I have this Mac for over one year but I never tried to use headphones to listened music until recent and the big surprise was: zero sound in my ears. After some research on the internet I find the solution: from Applications/Utilities/Audio MIDI Setup.app after you plug in the headphones you must uncheck Channel 1 and 2 from Mute column and this is all.
This was the most stupid thing what I sow on this Mac until now... and without internet help you have no chance to find this stupid setting.

Channel box in Maya

Like I said in the past I have some experience in 3D CAD design where the dimensions and constraints were everything. At the beginning in Maya I was lost, but I found very quick a good help and I am speaking about channel box.
By default channel box is the place where you can control dimensions, rotations, movements and other proprieties for every object from the scene. Later I found the control part of channel box, which is the place were you can have full control for any proprieties you want.

From here you can display or hide proprieties  and if the proprieties are displayed you can lock or unlock them for future modifications.
Channel box together with outliner and some shortcuts will be your day by day instruments for work and used together channel box and outliner will be your main help for debugging.