A System Administrator is like a Firefighter
Always available to fix an emergency, but without the glamour; after putting out a fire a SysAdmin has to report (with vague implications of guilt): what happened, why it happened, and how it can be prevented in the future. (Who's fault is it?)
Good System Administrators are well paid but usually work on the invisible and complex "back end" and are on "on call".
(Yes, your dinner, sleep, and other private activities will be interrupted.)
A stable, in demand, career since it's hard to fire a good System Administrator but there's often a belief that the position could/should be outsourced.
(Ever hear the story of the SysAdmin who was so good at automating server tasks and desktop deployments that he put himself out of a job?)
The overly general term "Operations" is often applied. In non technology focused companies you might be managed by a Chief Operations Officer who is more concerned with facilities (buildings), logistics (trucks, ships, planes, etc.) or even janitorial services.
If you're not careful, methodical, detailed, and cool headed then this may not be the right path for you. (Cynical is optional but it helps a lot).
An IT Manager is like an Accountant
Always asked to do more with less. In fairness an IT Manager gets to be more creative (legally) as innovation and change drive technological efficiency.
Good IT Managers spend as little time as possible in meetings but can organize and automate the heck out of everything. Diagrams, Business Cases, Reporting, Schedules; not often a hands on role.
Being in charge of IT resources is well paid and it's a stable career (you're in charge of the budget, right?) but when "downsizing" occurs you may be considered an acceptable loss (if your business cases prove you've saved/earned enough then it's usually a non issue).
Gluing together services often means jugging time zones (remote contractors and services are the norm) and balancing/network internal departmental demands.
If you're not good at understanding people or technology (yes you have to hire/fire people and purchase wisely) then this may not be the right path for you.
A Developer is like an Artist
Eccentric, misunderstood, and something rare for the Arts, well paid.
Good Developers understand it's Art with a purpose and apply rigorous engineering principles to their work (since software runs things like airplanes and hospitals this is a good thing).
It's well paid but sometimes unpredictable work (software project done = goodbye expensive labor), luckily there's an endless demand for the foreseeable future.
(Interestingly it often takes awhile to discover a "bad" developer and even then employers are reluctant to let them go).
If you're not creative and logical; unable to unriddle paradoxes (yes it's a required dependency but no we don't want it), or just don't want to spend most of your waking hours in front of a screen (human contact optional), then this might not be the right path for you.