Star Trek: 10 Worst Things Data Has Ever Done
1. Tortured Geordi
When you think things can't get any worse than your best friend allying himself with his evil twin and the Borg, it does.
Side note as we go; Data isn't totally under his own control here however it's not what you would pop round to tea for.
Captured by the Borg, Lore realises that Geordi can see the carrier wave which is controlling Data and has his brother perform further experiments on the engineer. Neutralising La Forge's pain receptors, Data inserts nano-cordical fibres into his head with the intention of destroying his existing brain cells. While it may well look like Data is setting up a game of Ker Plunk in Geordi's head he's actually planning on using the engineer's cranium to see if he can build an artificial neural net to take over his cognitive functions. Chances of survival; 40%.
Of course it's all forgotten about and washed over in a matter of seconds at the end of the episode but viewers must have wondered what the after effects of being tortured by your bezzie mate would have been. Also it's apparent Geordi didn't learn his lesson as we'll see next.