Which brings me neatly to the issue of the QNH / QFE debate!!
Plus the debate about whether it's a good idea to depart the field/circuit through the overhead.
(Yeah, I know that instructors sometimes teach students to depart through the overhead so that the first leg is flown wholly at cruise speed and levels, making timing of your first leg easier. I've never done that, but it sounds dangerous to me. I'd rather use an easily identifiable point a few miles away.)