For all the pontificating the seat should be more or less level with the handlebars and your feet while sitting on the seat should not be flat on the ground but on your tip toes a little bit. I can;'t adjust my handlebars anyway as i have a hybrid.

For a while i had my seat particularly low (all the way down) for tricks and downhill stuff but figured I'd use the extra power of full leg extension more than I need the freedom of movement of not having a seat in the way. Didn't bother me to ride like that but didn't get full range of motion on pedaling. When I 1st got it they said eh looks about the right fit and they didn't adjust anything.

I do feel like I'd like my handle bars a tad higher so i could sit straight up sometimes but it's a hybrid not a cruiser so I think it's meant to be a little forward and aggressive like that. I'd shorten the whole bike by an inch and raise the bar a tad. Maybe i needed a smaller size but I'm 6'2, L is likely appropriate. I could maybe Move the seat all the way forward and a little down, might be better.