The disappointed "oh"

The oh-now-I-get-it "oh"

The "oh" that usually precedes a profanity or something relatively similar

The shocked and startled "oh" 

The "oh" that is followed up with an awkward pause

The trying-to-sound-cheerful-to-hide-broken-expectations "oh"

I think I've had my fair share of disappointed and trying-to-sound-cheerful "oh"s