Ice Cream Trucks - When I was in Miami, the ice cream trucks blared "Pop Goes the Weasel", "Happy Birthday" and several other children's songs over and over again and they would stay in the neighborhood for over an hour at a time.  I really just wanted to blow the d**n speakers off of the truck.  I grew up with bells that, as a kid, I could hear in plenty of time to plead the necessary quarter out of my mom.
Grocery Carts - I have walked up to people and commented on how amazed I am at how lazy they are.  My DH hates it when they make it to the cart corral but do not bother to push the carts together to make room for the next guy.
My Biggest Pet Peeve - people who throw cigarette butts on the ground.  The butts are not biodegradable.  They are full of toxins.  They can start fires.  They are not pretty.  They are gross and disgusting.  You can tell how long a stop light is by the number of cigarette butts in the gutter as long as you take into consideration the last time it rained.  The number one clean up item on beaches and in rivers is cigarette butts because people do not take responsibility for their trash.  When I was a little kid (under 6) I would pick them up off of the ground and put them in my mouth because I wanted to be like mom and dad.
AAAAHHHH!   Venting!   I feel so much better.  Thank you for the opportunity.