The Isle of Lemnos in the myth of The Argonauts. An island full of beautiful warrior women who claim all their men are away fighting. Of course you can stay as long as you want, eat and drink the food, help yourself to their treasures and have your way with the women. They frequently sacrifice men to Artemis once they've drugged them with the wine. Thankfully, the lone female Argonaut isn't fooled.
All she had to do was not open the box, and everyone would be happy. But no, she just had to see what was inside. So she opens it.
Some variants of the myth support the box being the bait, while others support the concept that Pandora herself was the bait.
The rather misogynistic writings of Hesiod claim that Pandora was created as a punishment for man, so that all her descendants, e.g., women, would torment humanity. All men had to do was not accept her as a gift and they would be free of the associated evils, but they ignored all the warnings about accepting gifts from the Olympians.
Still other versions say that Pandora could never have left her urn unopened; the Olympians had given her insatiable curiosity along with her many fine and desirable qualities.
There is also Epimetheus' role. He was warned by his brother Prometheus not to accept any gifts from the vindictive Zeus since it would only cause trouble. Pandora was given to Epimetheus to be his wife. Unfortunately, Epimetheus was the Titan of AFTERTHOUGHT who acted first and thought later, compared to Prometheus, who was the Titan of FORETHOUGHT, thinking first.
There's also the story of Orpheus, who went to the underworld to retrieve his dead wife, but was warned not to look back at her before he got back to the world of the living. He looked back. She died again because he did wait; he just didn't wait long enough. He was out of the underworld; she was not. Not completely, anyway. Additionally, Hades made her follow him in complete silence.
Psyche:
Psyche nearly averted this. When her husband Eros told her never to look upon his true form, she was perfectly fine with it until her sisters convinced her that he might be a hideous monster (despite that she had previously felt his body and had plenty of chances to feel his face). At least she only had to deal with a Mama Bear that was already mad at her, instead of the Deader than Dead fate that usually befalls those who look upon undisguised gods.
But when she was sent to bring back the beauty of Persephone in a box, she peeked; either the beauty was overwhelming to a mortal or Persephone had guessed Aphrodite wanted to get rid of Psyche without ticking off Eros. Luckily, Eros had decided to reconcile and came to save her.
The Iliad: A golden apple, labeled 'Kallisti' — to the prettiest. Notably, it's successful Schmuck Bait to the Goddess of Wisdom.
The Odyssey. "Hey, we're a bunch of incredibly hungry sailors on an island inhabited by the juicy-looking cattle of the sun god! What's that, Odysseus? We can't eat them? C'mon, what could happen, it's not like we can piss off the gods even further..." They decided that whatever the gods were going to do would be better than starving to death while stuck on that island. (And they might not have been particularly wrong — drowning may or may not be a particularly nice way to die, but it's better than starving.)
God put a tree in a garden and (paraphrase) said, "Don't eat this fruit. It will kill you." That's right God invented Schmuck Bait. Alternatively, Adam and Eve invented Schmuckitude. Alternatively alternatively it was both. A clue may be in that Eve's rendition of the prohibition had an additional part against touching the fruit that wasn't in the original. Which makes sense; if you're not going to eat it, there's no reason to intentionally touch it. Well, according to tradition, the serpent backed her into the fruit as he was talking, thus proving that touching it wouldn't cause death, and casting additional doubt on the veracity of the real command.
Also, Lot's wife in The Bible. Do not look back at the dying cities. Do not look back. DO NOT... Salt, anyone?
Proverbs 1:17 says "surely in vain is a net spread in the sight of any bird." Meaning someone would have to be very stupid to fall for a trap being laid out for them when it's pretty obvious that it is a trap.
Other
To get back at Cuchulainn for knocking her up and then marrying Emer instead, Aoife sent her son out into the world with two conditions: Challenge every warrior he meets, and never ever ever reveal his name. Naturally, when Cuchulainn gets challenged by some kid, cue the Curb-Stomp Battle. Then Cuchulainn notices a really familiar-looking ring...
There's also original "Damned if you do, damned if you don't" fairy tale, sometimes named "Dark world". A king and his companions were on a quest and, in their wandering, ended in a cave-like, long, underground passage. They kept moving until they reached a part of the passage where no light could be started or exist (titular "Dark world"). They felt rough things, or pieces of things, under their shoes. Suddenly, a voice was heard: "If you take those, you'll regret it. If you don't take those, you'll regret it." Some people chose not to take the things, some chose to take one or two, just to see what all the fuss was all about. Then they moved away from the weird things. Finally, after three more days of wandering and lots of danger, they exited the cave. After they looked in their pockets, they found they had rough diamonds. Now, those that didn't take anything, regretted it, and those that did, regretted they didn't take more than one or two!
