Learn to justify (in your head) other people's code. It's just too easy to hit programmer's block because of existing code is written badly and needs refactoring. Instead of immediately re-writing and re-testing everything, try to find some perspective from which that code would seem more reasonable. Your perception of code depends a lot on how you look at it. It can be hopelessly bad, or be slightly out-of-date at the same time.
Example: for a long time I hated visual studio .sln and .vcproj files "poluting" my folder structure. It bugged me that my main folder should start with some application specific configuration files. I saw other people's projects that had folder structures like:
ProjectA\
ProjectA\
ProjectA.vcproj
...
ProjectA.sln
And it made sence to me, simple and elegant. But still, for own "ultimate" projects, it was too poluting...
Well, finally I found a perspective, from which this folder structure made sence - think of it as a generic file listing. Those .sln and .vcproj are just some standard, that is common enough to be chosen for declaring all the files in all subfolders. Kind a like declaration of functions in c++ header files. It's just there for Your convenience, and at the same time it can be used for pre-compiling executable binaries from c++ code. Sure, it's xml-format is improssible to read or modify, but for now we can ignore that. As long as it saves time for us to start new projects we can live with it.