It used to drive me crazy and I decided to tinker and solve it. To fix, do the following:
Once iTunes is loaded, select Controls from the Menu and note down what the menu options are called. Currently, they are called Next & Previous.
Go to Settings from the dock and select App Shortcuts.
Click + to add an iTunes Shortcut.
Name the shortcut EXACTLY as the Controls. So type Next. Now press JUST the >> key on your macbook.
Click + to remap Previous. Name it Previous and press the << key to map that shortcut.
Done!
PS: This won't work if iTunes is not the active app. So if you're using some other app and press the shortcut, it's not going to work and change the song.
You can work around that too. I did not think it wouild work but it did. Do the same thing. Create a new shortcut. Call it EXACTLY iTunes.
This time, do it for 'All Applications'. Use the Play >= key on your keyboard to remap it. Now if you're browsing the internet and you want to skip the song, it will take 2 keyboard clicks to do that.
Press >= (that you remapped) to bring iTunes into focus.
Press >> and it will skip the song.
The latter does not always workwith all apps. Or at least it only seems to work with Chrome. I can be browsing and change the track with the keyboard keys as above.