11 things I learned reading the flexbox spec
David Gilbertson

One of the things I always liked about flexbox is that intead of using left and right it uses start and end. When you need to produce rtl / ltr layouts this is very handy (just switch flex-direction and voilà).

I admit most of my flexbox experience is through trial and error (never had the patiance to read long posts about flexbox) so I didn’t know margin-left/right was the proper way to pull a block a certain direction.

I’m a bit disappointed they broke this abstraction.