PowerShell: You must think in objects
Yes, Firefox ("You must think in Russian") is one of my favorite movies :)
Even now, I still find myself thinking cmd-ish at times and forgetting how much easier life is in PowerShell.
An example from yesterday was doing a dir -r -filter to look for a set of files in a tree. Then I realized I wanted to delete all of them. My knee-jerk brain reaction (too much cmd.exe time) was along the lines of doing a for loop with "dir /s /b". Then I remembered - oh, yeah, these are real objects - just pipe the output to remove-item and be done with it.
Dealing with real objects all the time is a great shift, but I still find myself trying to remember the power that's available - it makes a lot of things much easier, but only if you remember you're holding the keys to the Ferrari in the first place. :)