I hate that margin / padding short-hands, especially with 2 values, expect vertical first.
In my head it's always (x,y) and (width,height) – always horizontal then vertical, I feel like it works like this everywhere else?
Now my issue is that I've committed to memory that margin and padding short-hands work the exact opposite way I would expect, so sometimes I still mix them up because I type them 'correctly' and then flip them because I memorized it like that..