Is it bad practice to return a variable and not use it?

[terrancepython11]

You answered the question yourself.  Basically, you don't want to write code that will make your program more difficult to reuse or debug.  In other words, code should be clean, and minimize errors, because as you write more complex programs, you will have difficulty debugging the code as your programs get larger.  Further, object oriented programming is based around the idea of making your code easier to debug and reuse.  So with that said, you should practice good programming principles and not return values from functions when they won't be used.