DM: An arrow is fired at you from the woods. Role an acrobatics check to dodge it
Half-Elf (Me): *rolls nat 20* Hell yeah!
DM: *rolls high for the arrow* Okay so you dodge the arrow but it bounces off the tree and goes towards the Dragonborn
Dragonborn: *rolls nat 20*
(The arrow ended up bouncing off the trees repeatedly until eventually hitting the Dragonborn in he crouch on a nat 1)