How about a paintball pellet right in the middle of their windshield?

Would make 'em think... geez, what if it had been a .45 ?

Gummybears. Wet them in your mouth (maybe small chews, too), spit em. They stick and peel paint. Plus then they have a massive, expensive bohemith with colorful bears smiling away from them. Brightens everyone's day.

As I suggested earlier...slap these on the back window of the car in question.

Quiet yet lets the world know what an A-hole driver this person is.

You know what would be really cool - some sort of gun like the ones that they use in supermarkets to tag merchandise, only with a lot bigger stickers. The problem with stickers is you have to peel the backing before you can use them, and you're already going to be all frazzled and shaken by the incedent, then you have to catch them. A piece of paper can be dropped in an open window easily, but a sticker is way harder. And open window is pretty rare around here, too - it's always either too hot or to cold for them.

Wow. Those made me smile

I spit a hard candy I happened to be sucking on at a cab, driver's side window which made a loud noise and seemed to get his attention. Hard bang with fist on roof right over driver's head gets noticed too. I've done worse but it's dangerous to hit a beloved automobile with your lock. I thought I could escape a van I hit w my lock but when he kept chasing after I went the wrong way on one way street, I gave up, had to apologize explaining that he had frightened me and I reacted out of fear (basically asking him not to kill me in different words).

hahaha...good one!

Big f'n loogie.

No property damage and I always feel a lot better. It really seems to piss drivers off.

There was a guy about a year ago who went on a rampage and destroyed like 2000 car windows in london i think it was. Do that. Remind yourself that there are no innocent car drivers!

Was it london? Anyone remember? He was a few rocks short of a pile.

It was somewhere in England (maybe London), and he punctured about 2000 tires.

Cyclist's tyre slash vendetta

James Sturcke
Thursday March 25, 2004
The Guardian

A cyclist angered by motorists' behaviour was warned that he faces a jail term yesterday after he admitted taking revenge by slashing more than 1,700 car tyres, causing damage amounting to £250,000.

Ashley Carpenter, 37, began a 10-day vandalism spree after a car nearly knocked him off his bike and another drenched him by driving through a puddle.

Bournemouth magistrates were told he left his home by bike at night armed with a sharpened screwdriver and randomly punctured tyres on nearly 600 cars parked in Bournemouth and Christchurch, Dorset.

Carpenter, unemployed, admitted eight charges of criminal damage last December and asked for 540 similar offences to be taken into consideration. Sentencing was adjourned.

The court heard that at least 1,728 tyres were damaged. Julia Woodward, prosecuting, said: "He struck on roads, in private car parks, in public car parks and in people's driveways."

She added: "This scale of offending was unprecedented and caused immense distress."

He was arrested after the police studied CCTV pictures.

I can't take credit for this one, it's my friends idea...

here's supposedly a product called "glass etch" or something like that...and it eats away at glass...
the idea is to carry around a squirtgun willed with the stuff, if anyone messes with you, simply ride up to them, and spray it on their windshield...I doubt anyone would take offense to being squirted by a squirtgun, and most likely they'll think you to be a wuss and just laugh at you...
meanwhile they'll use their windshield wipers, thus spreading the glass etch all over the windshield...the next day the'll arrive at their car with their windshield completely F*CKED UP!

it might be a delayed gratification, but you'll smile the whole time

this is the truth, like it or not... i've mellowed out in my "old" age..
but if 'yer a punk, and don't give a $h!t, i'll share my techniques. i've already ruined my rep on this site for being a poor ambassador to motorists.
1) learned this from an old hell's angel- carry a couple ball bearings in your pocket- industrial size. i got some 3/4" and 1"-ers from a compressor pump. a simple, underhanded toss into the windshield of a moving car will go through. if the car has already passed, you can throw those dense little suckers with amazing range and accuracy. the spark plug thing is an urban myth.
2) use clipless shoes that accept screw-in track spikes. usually two 'fangs' up front. works as a knee-jerk reaction to closely passing cars. woks on paint like a key.

this is provided for informational purposes only, for the sake of discussion and must not be taken out of context. the author is not liable for illicit use of this information. (keep the prudes at bay!)

it's probably hydroflouric acid. which you definitely wouldn't be able to carry in a squirt gun and wouldn't want to be anywhere near.

the scope for major collateral damage is way high too.
https://www.emedicine.com/emerg/topic804.htm

fsnl
sparky

hydroflouric acid is a major precursor to sarin nerve gas. welcome to the national security watch list.

my dad races road bikes. he got cut off by some ******* in a convertible a few years back. he caught up to the guy at a light and was able to reach in, grab his keys, and throw them off the road. doesn't get much better than that...

Of course after you do some of this stuff to someone, you always have to wonder when they'll be behind you again.....

I have keys hooked to my one of those mountain climbing clips and they're always on my shorts somewhere. Piss you off... go by at about 15kph hold it out and key away.

Here's a good idea:

Don't do anything to the car or driver.

Be glad you're not hurt. Instead of getting angry, replay the event in your mind and figure out what you might have done to avoid that situation in the first place.

Wow, that's the most intelligent reply yet.
A rarity on these whiney forums.
Can I use it in my signature?
I treat traffic like the wind, or any other forcce i deal with.

Uh, no. It works. I haven't done it myself, but they had it on the news here, and I saw it in action. People use it to steal stuff (purses, CDs, etc) out of cars all the time here.

It's not rocket science people.

A center punch works even better, many people keep one in the car door pocket if they're paranoid about being in deep water in their vehicle.

Instant escape.

Yeah, it's just the way that saftey glass works. Pretty much anything will cause it to shatter - that's what it's designed to do.

What is a center punch anyway?

Ahh, a voice of reason...

kind of like an ice pick only thicker.
about 5/8 on one end, has a sharp tip tapering for the last inch to half-inch.
Maybe 6-8 inches long and hardened steel.
It's used for making a dent in metal on scribed lines. (you smack it with a hammer)
The drill bit seeks the dent as it's center.
Picture weight or force concentrated onto a sharp point.