walking towards someone who cant walk in a straight line! they zigzag all over the footpath then when they're about 10ft away decide they will happily walk straight into you ather than make any attempt to move out of the way!
the worst is people who walk in front of you in the street or in a corridor and just dawdle along either with someone else or on thei own but in such a way no can can get past them!
whenever i learn something new it pushes some old knowledge out of my brain, remember that home wine making course when i forgot how to drive?!