Comments related building something and being creative:

This great feeling when you produce a piece of art that works! (and is usefull)

Creating stuff that is useful

The ability to make something from nothing

The creativity a programmer has to explore all posible solutions to a problem

Comments related to problem solving and a sense of achievement:

Sense of achievement when something comes together

The Eureka moment - when it all just works

Solving interesting challenges in a real way

Making something that works and looks good - commercial standard

Comments related to having and impact and changing the world:

It is a new science that we are only starting to discover, there's always something new to learn

The far reaching multidisciplinary potential

It can and does change the world

Being on the leading edge of technology and development

Opportunities that computing enables for all other uses

Comments related to compilation issues and not finding a solution:

Programming bugs that keep you up for hours and then its just a ';'

When the program/algorithm doesn't work as you thought it would and you don't know why!

Coming up against difficult obstacles (often!) when coding solutions to complex problems.

Comments related to working hours and where you work:

Long hours, stress, frustration

Much, much more work than anyone else seems to get!

Staring at a computer screen all day is rather taxing on the eyes

Any computer-related job means sitting at the desk in the office - and there's no way to avoid it.

Comments related to peoples perception (such as IT vs CS) and type of people:

Not enough women!

40:1 male-to-female ratio

(Sometimes) the people you work with

Everyone asks for tech support as soon as they know I'm studying computers

Too many software engineers masquerading as Computer Scientiests! Oh, and everyone thinks you can fix their PC/phone/etc – but I’ll always try ...

Comments related to documentation and design:

Interface design, web design, needless writing of documentation

Formal requirements etc.

Paperwork, bueracracy (which clearly I can't spell :-) )

Comments related to legacy, technology and change:

Legacy

The speed at which technology develops.

The computers!