This prompt from Writing.Prompt.S would create quite the crazy dream. It could be torturous for the person involved. I mean can you imagine living in the 18th century, the 1700s with 21st century knowledge?
I do not pretend to be an expert in 18th century technology, but we can definitely say that indoor plumbing though not non existent during that time, we not really a thing most people had during that time. The first computer like object we know about wasn’t created until the 19th century either and forget TVs they didn’t even have photographs outside of one known experiment at the beginning of that century that didn’t really take and radio wasn’t even a dream in anyone’s mind..
The sheer level of technology we have today that didn’t exist in the 18th century and the different amount of knowledge we have now verses then would be enough to mess with anyone’s mind in a situation like this.
A person in this sort of situation is most likely to do one of two things: change things or go crazy. They could opt for ignore it all, but we are talking about someone who woke u[ from a coma with full memories of things two to three hundred years in the future depending on what part of each century we are talking about.
At the bare minimum someone with 21 century knowledge is going to take note of historical events that will take place during their lifetime and make sure that they either aren’t there or are, depending on what those events are and what they want with them. A war coming between England and her colonies? Get out of England or the Colonies, depending on where you are. Or maybe try to get an audience with a general in one of those armies that will change the course of the war.
Or maybe you can move to California. Start the gold rush a century early. Or don’t, but mine the gold anyway.. The things you can do with future knowledge are massive. What would you do with this kind of situation and would your character do something different?