A person who always under estimates the time necessary to do something or get somewhere.
"Hey, Cindy. you know my parents are expecting us in 20 minutes."On a very personal note, if chronoptimist was actually in the dictionary, there would be a picture of my mother beside the term as an example. Don't get me wrong, I love my mother, but this word was surely created to describe her.
"No problem. I just have to wash the dishes, take a shower, do my hair, walk the dog and then I'm all good to go. See you in 15."
"You are such a chronoptimist! I'll see you in 45."