As a system administrator you hate to see it happen:
A user has a problem. They don't report it to you (enter a bug report, file a ticket). They whine to their friends, or suffer in silence. Months later you find out and ask, "Why didn't you file a ticket? I could have fixed it!" They either didn't have time, didn't feel it would do any good, or whatever.
What's 100 times more annoying? When sysadmins do it to each other.
I've seen it many times. Walking through a process (say... setting up a new machine) and some of the steps require... umm... "interesting work-arounds". I ask "is there a bug filed about that?" and am told, "No, they know it's a problem".
Oh do they?
Things can't be fixed unless someone knows it is broken. Assuming that someone knows about a problem is assuming that everyone else has ESP. Don't expect your coworkers to be mind-readers.
In a recent case the person told me "they know about it" but it was a task that he was responsible for doing. The others wouldn't possibly know about this problem unless he went on vacation and the task happened to be needed. That wasn't likely.
When we use a service we often know the "client" end of things much better than the people responsible for the service itself. Don't assume they use the service they provide as much as you do!
I would rather have a duplicate bug filed than no bug filed at all.
These problems, inconveniences, inefficiencies, "issues", "could-be-betters" and "should-be-betters" need to be recorded somewhere so they can be prioritized, sorted, and worked on. Whether the list is kept in a bugtracking system, helpdesk "ticket" system, wiki page, or spreadsheet: it has to be anywhere other than your brain.
In Gene Kim's "Three Ways" the 2nd way is the "Feedback" way. Amplify issues, don't hide them! If there is a process problem you are working around, file a bug report. If there is a crash make sure the programmer gets woken up at 3am so he or she feels the pain too. If a process has a "long version" that is only needed "occasionally" then publish how many times each month the "long path" is needed so that people are aware just how occasional "occasionally" is.
Speaking of The Three Ways, Tim Hunter has re-interpreted them in a much more comprehensible way in this blog post on IT Revolution. I highly recommend reading it.