Here's what we know:
* It's a relatively modern phrase: The earliest recorded use of "toughen up, buttercup" seems to be in the late 20th century, possibly around the 1980s or 1990s.
* It's a playful insult: The phrase is used to dismiss someone's complaints or perceived weakness in a lighthearted, sometimes sarcastic way.
* It combines two distinct elements: "Toughen up" is a common phrase encouraging someone to be more resilient, while "buttercup" is a small, delicate flower, suggesting vulnerability.
* It's likely a combination of influences: The phrase may have evolved from similar phrases like "toughen up, cupcake" or "suck it up, buttercup."
It's important to note: While the exact origin remains unclear, the phrase has become a popular meme and catchphrase in recent years, especially online. Its popularity likely stems from its simple, memorable nature and its ability to convey a sense of playful mockery.