I rarely (read: never) want to tweet when I right click to bring up a context menu. Actually, most of the time, I'm just looking for "Inspect Element" in Chrome. I was happily surprised to find I could remove the option entirely:

1. Open System Preferences
2. Choose "Keyboard"
3. Choose the "Keyboard Shortcuts" tab
4. Find "Services" in the menu
5. Untick "Tweet" (I also found a few others to untick)
6. Profit