The only time I had a sysadmin hate me it was more due to me documenting their dangerous incompetence.
After a security hole was found in our multi-million daily users web application I was given a project to look into other potential security issues with the application. After trying SQL injection, cross-site scripting, and other fun stuff I started to poke into the application server it was running on, and a quick read through the documentation told me how to get diagnostic information from the system- unless it's been disabled as part of the standard installation process. I try it on my dev server, and get the info- not a problem. I try it on the test server and it's the same. I then try the staging server, which should be a copy of the live service, and start to get scared.
After a quick chat with my manager as I wanted to be covered should the system flag me as an attacker I try it on the live service from an external IP address, again the diagnostics appear. I now had our database schema, the network architecture of the live service, and a lot of configuration details. My manager, who'd been watching over my shoulder as they'd become curious now, suggested we test this properly. I used my non-work mobile and called the sysadmin and, using only the details on screen, convinced him I was a database admin from elsewhere in the company working off-site. He was very helpful, I soon had a nicely unofficial SSH tunnel into the network set up for me, a temporary user account on all of the live servers, and root access to the live database with all of our customer details.
Oddly enough the sysadmin didn't think it fair that we'd 'tricked' him, and said that no one would normally see that information and think to do what I'd just done.
Most sysadmins I've worked with have been very good, and the in-department one I'm working with at the moment is absolutely amazing. It's not the case with all sysadmins though, some of them don't need users running random software as root to make things go stupid.