I don't know the history of these characters, but I have always found drinking coffee makes me tired after a short energy burst. So I'm curious to understand the context!
Sugar also makes me tired but I think that's well documented (sugar crash).
The characters are from the TV series "The owl house".
Amity (the pink-haired one) and Viney (the gal in the last vignette) are witches from the "Demon realm", a different dimension that houses witches and demons. They eat totally different things from humans and their food is inedible to humans, and human food can have different effects on them compared to humans.
Which means that you could be a witch! Congratulations!