jaded view of your application. For instance, spending a lot of time in the product for testing purposes can expose you disproportionately to the issues that have been triaged away to the future in the expectation that customers won't encounter them (often, for now). It's easy to take the skewed exposure and obtain a skewed perspective.
Alternatively, it's also undesirable if understandable that, when looking for errors and finding them, and then retesting their fixes, and then reretesting their refixes, aspects of the application, the process, your team mates, your version control system and the like will begin to grate.
You should do everything you can to keep a lid on these kinds of frustrations, and carefully choose your moment to bring them up. It's right to care about the AUT but it's not right, or productive, to let your gripes out at every opportunity. One of the strengths of the best testers is being respected for their opinions, not being thought of as the J (or for students of classic comedy, the N) in irk.