Inns with irritating/eccentric landlords (lights out at 10, temperance village, demanding the PCs take baths, only food available is what you pick yourself, that sort of thing)
Goats that go bleat in the night (in a threatening manner...) (watch that blood pressure rocket :) )
Shoe catastrophes (how many PCs have the gear to mend their boots ?) or even worse, horse maintenance
Local Govt. representative charging them road tax (my lot thought it was a bandit scam, and killed them...bad move). If they pay up, you can even give them a road tax disc...
Helpful NPCs who just want to make their life easier (offering cups of tea, somewhere to stay, in a quiet cottage in the woods, "if only you'll chop some wood sir, for I am frail" kind of thing - eccentric old ladies with too many cats who really are just being nice)
Bridges down, flooded rivers, natural catastrophes in all shapes and forms (especially irritating ones that are time consuming, or involve a change of plan, without being life threatening)