On the narrow San Francisco streets, drivers park bumper-to-bumper while dodging street cleaning signs, blue zones, red zones and yellow zones.
"You have to have a sense of humor to own a car in this town…because it's a challenge to drive, to park and to keep your cool," Amy Keyishian said.
When neighbors lose their cool, that's when Keyishian says she starts finding nasty notes on her windshield.
The internet is littered with pictures of passive aggressive parking notes -- ranging from the sarcastic to the obscene. You could argue those are from the "nice" neighbors; the not so nice ones might just call the parking patrol.
"A lot of people have one of these, which is the sign that you put up saying, 'Oh please don't tow me just give me a call,'" Keyishian said.
But now, Keyishian has something else on her car -- a little round sticker next to the license plate.
In fact, if you walk down Precita Avenue, you'll see dozens of cars now sporting the tiny logo for CurbTXT.
"The sticker basically indicates to their neighbors that they're part of the CurbTXT network," CurbTXT CTO Andrew Sotzing said.
Just punch in the license plate number and you can send a short, anonymous message to the car's owner. It's a free service created by a trio of enterprising young neighbors.
"We were just trying to solve that problem, how do you communicate to someone you don't know, but you know their car is there and you want to reach them," CurbTXT co-founder Alex Maxa said.
Though we live in an age of apps and smartphones, CurbTXT is actually a bit old fashioned. There's no app to download; instead, you interact with the service by sending text messages. That means it will work on any phone, even an old flip phone.
"We're proud to say that just a week ago, the first neighbor-to-neighbor CurbTXT was sent, and someone was letting someone know that their car was about to get ticketed," Sotzing said.
The founders say 300 people have already registered. They're giving away the stickers at local coffee shops hoping neighbors will start looking out for each other instead of writing nasty notes.