What's more comical, watching a shorter person clambering over a fallen tree, or someone taller scrambling under a tree!?
I'm probably on the taller side, and it definitely has its advantages in most terrain, but when it comes to off-track scrambling (or unmaintained tracks), its amazing how many trees/branches fall right at that uncomfortable decision height.
I know that when I choose to go under a branch, no matter how often I tell myself to keep down, down, down... I nearly always come up too early...it's all the fun of the game, just when you think you've timed it to perfection (minimising the exertion), that damn 1mm thick vine traps your bag, and you wrestle for an inordinate time to get clear.
On the other hand when you go over the branch, and the footing on the other side is just a little bit further a drop than expected, and you're left straddling uncomfortably whilst you tenderly lower yourself down.
Also hitting your head with the rain jacket hood on is annoying. I now tend to walk with my hat on, and the hood over the top, and have reduced my obscenities by 80%.....the joys of hiking.