American English doesn't typically denote sarcasm with punctuation. Thanks! is genuine. But emphasis or additional words can make it sarcastic:

• Gee, thanks.
• Thanks *a lot*.

I've also seen younger generations (born 1990+) use trailing letters to denote additional emotion that is not necessarily sarcastic: Thanksssssssssssss! I don't get it.

American English doesn't typically denote sarcasm with punctuation. "Thanks!" is genuine. But emphasis or additional words can make it sarcastic:

• Gee, thanks.

• Thanks a lot.

I've also seen younger generations (born 1990+) use trailing letters to denote additional emotion that is not necessarily sarcastic: "Thanksssssssssssss!" I don't get it.

American English doesn't typically denote sarcasm with punctuation. Thanks! is genuine. But emphasis or additional words can make it sarcastic:

• Gee, thanks.
• Thanks *alot*.

I've also seen younger generations (born 1990+) use trailing letters to denote additional emotion that is not necessarily sarcastic: Thanksssssssssssssssss! I don't get it...

American English doesn't typically denote sarcasm with punctuation. Thanks! is genuine. But emphasis or additional words can make it sarcastic:

• Gee, thanks.
• Thanks *a lot*.

I've also seen younger generations (born 1990+) use trailing letters to denote additional emotion that is not necessarily sarcastic: Thanksssssssssssss! I don't get it.