For most people who have been on XC/track teams hills mean pain. Usually the name of the street where your coach had you do hill workouts can bring a chill to the spine many years later. At my high school we had "5th street." Our coach marked out 400 meter and 800 meter "options". University of Michigan has Harvard Street - which is shorter, but steeper. At Loyola in Chicago we were forced to go to a sledding hill in Evanston that had once been a dump - it was too short - so we did a LOT of them.
The worst thing about hill workouts is the last 25 meters when it feels like you're standing still, and yet your legs are burning and you feel like you might hyperventilate. But, they make you stronger.
In preperation for Boston I'm going to do hills on most weeks when I have just one other "hard" workout. I may even do some downhill training as I've heard that the Boston downhills near the end are more challenging on dead legs than you might think.
This morning was my first hill workout in Druid Hill Park (pic above). I tried to take it a little easy on myself - but, I still got a good burn going.