I'd say that I've noticed a difference between the type of grumpy I get because the things that normally wouldn't bother me, bother me.

Like... I'll get EXTREMELY PO'd at my cat for meowing. Just one meow. Or I'll get annoyed as all crap if he wants to cuddle up (who gets mad at a cuddly cat?!?!). Have flipped out on my students because SURPRISE they talked when they weren't really supposed to. They do this every day and I am normally good natured about it because when we DO end up quiet... it's usually me who breaks the silence!

Normally if I'm a "normal" grumpy there's a bit more of a reason for it - like something that ISN'T an every day occurance, or if it's something that really shouldn't be happening (eg for the past month there's been a cab parking between my spot and the entryway to the building... I don't have a car but the fact is, that's NOT a parking spot. So I let the rental company know. That's a legit thing to be annoyed about!)

Also if I'm in a normal sort of grump, it's very situational and will be done and over shortly. If I'm getting annoyed with EVERYTHING that normally wouldn't bother me... it'll kick around longer.