Doing it wrong all this time!

[m_c]

It's not about which is the longest axis, it's about orientation. The one parallel with your belly is the X, the one moving AWAY from your belly is Y and the one moving towards your head from your feet is the Z.

[Ger21]

I didn't read all of the replies,but your Y axis is backwards. If X+ is to the right, then Y+ moves towards your wall in the back.

[Boyan Silyavski]

There is only one right way to do it. There is a certain rule how to find the coordinates in a Cartesian system and if not learned right you can make a very BIG Mistake on a machining centre or when you have more than the 3 axis. Take that 5 min effort to learn things right.