What memes or bumper stickers actually make a good point?

Me too.

You entirely missed the point.

Other ways of saying it:
Enjoy the sweetness of your beautiful, finite life!
Don’t put off doing the things that matter until it’s too late.
Live for today for you don’t know what tomorrow holds.

It’s true, it’s a “morbid” way of saying it, but that makes it hit home, while the more upbeat motivational-poster ones are easily ignored. Many people who have near-death experiences are gifted with a wake-up call pretty much like that bumper sticker.

“The Fact That No One Understands You Doesn’t Mean You Are An Artist”

Good one.

plus one.

“Ignore last bumper sticker”. (Also seen on clothing “Ignore last t-shirt.”)

Every grandparent’s favorite:
“If I knew how much fun grandchildren would be, I would have had them first.”

Then there are the bumper stickers which play off of previous bumper stickers:
“My boss is a Jewish carpenter. We call him Sol.”

Ukrainian troops are at home.

At any rate, the ones that haven’t been forcibly hauled off to Russia; and I expect that Ukraine would like to support those by bringing them home, too.

Yeah, I never agreed with that one. Not voting encourages “them” even more.

– there are quite a few good ones in this thread; I won’t clog it up by trying to quote them all.

As to the various voting mems / stickers, the pithy one I like most is

Zing!

Although in truth, voting in the final, or even the primaries, is way, way, way too late in the process of determining who’s in charge. To actually wield proportaional influence, the 99% needs to play heavily back at the “Who’re the bigwigs in your local party chapter?” stage of politics to have real influence. More easily said than done.

My response to “Throw the bums out !” has long been … under our current system, there’s a long, long line of functionally identical bums behind them.

I’ll second that. Have you ever read Heinlein’s Stranger in a Strange Land? There’s a scene in the book in which Jubal Harshaw, a main character, is trying to explain art to another guy. He says art has to tell a story, to move the person looking at it, and NOT be something the artist does to show how much more sophisticated they are than the observer. I also like it when he says “These days any idiot with a blowtorch can call himself an artist.”

Or, as seen in a doctor’s office on the wall above the scale (really!): Eat, drink, and be merry, for tomorrow we diet.

Another variant: Life is short. Eat your dessert first.

I like the “Enjoy every sandwich” bumper sticker. Thank you Warren Zevon for that very insightful saying.

Northernsun had one that said “Mean People Suck.” I wanted one that said “When Mean People Suck, What Do They Mean By That?”

“Lysdexia Socks.”

You used to be able to get a bumper sticker at cons that said,

“Campus Crusade for Cthulu. It found me!”

Have your seen the follow up bumper stickers?

“Mean People Suck. Nice People Swallow.”

As far as stickers that might fit the OP, I’m partial to this classic commentary on defraying the high cost of living:

“Gas, ass, or grass: nobody rides for free.”

I saw a cartoon with a guy carrying a picket sign, Please Help Daily Sex.

One onlooker is saying to another, “The Dyslexia League really needs to outsource their signs.”

“Did you hear about the dyslexic agnostic insomniac ?”

“He stayed up all night pondering the existence of dog.”

Bumper sticker I saw once (really!):
Bee healthy! Eat your honey daily.

I once had a t-shirt that said, “Exercise hard, eat fiber, die anyway” and it was accompanied by a cartoon animal with a jump rope and a saggy headband.

I can also appreciate a meme that says, “If you keep pursuing something, and nothing comes of it, it was not meant for you.”

T-shirt from the '70s:
Eat a beaver, save a tree.