First, in the episode "Datalore", it is established that Data can't use contractions. However, when Data beams his twin out into space, the captain asks if he's alright, to which he responds "Yes, sir, I'm fine." Is this just because he's still got Lore's facial twitch? I really don't think so...
Also, on a different episode... Or rather, episodes. Specifically, "Encounter at Farpoint" and "The Big Goodbye". (I noticed there was a little posting on Starfleet's continued use of the holodecks, so I thought I'd add in my two cents.)
In "Encounter at Farpoint", Wesley falls in the water and comes out of the Holodeck soaking wet. Now, since most things that leave the Holodeck disappear (see "The Big Goodbye" or any of the episodes featuring Moriarty from Data's Sherlock Holmes program) it would be assumed that Wesley should be perfectly dry. Since he is not, we must assume that certain elements of a holodeck are not illusions, but are instead real in some sense....a replicator comes to mind? Why couldn't specific items in the holodeck be replicated? This makes more sense if you take into account the amount of food items that people in the Trek universe consume in the holodeck. If those nutrients were processed by the body and integrated into their physiology, then removal from the holodeck would cause the nutrients and possibly key elements of a person's body to vanish, causing all sorts of medical problems. (To carry this out, a person living in a holodeck could eventually be nothing more than a projection, and therefore either be immortal due to the unlimited potential of a holodeck, or die horribly at some point.) It would seem, therefore, that Starfleet would include a replicator function to help NOT kill a person with continued use of the Holodeck. This would also explain Wesley's clothes not drying out after his tumble in the lake...and it was such a poor tumble in the first place...
Now, onto the next episode... In "The Big Goodbye", the holodeck malfunctions for the first time and the crew is trapped inside. The episode analysis states that the holodeck seems to have no failsafe. Here's a theory: What if sealing the crew inside and turning the safety protocols off IS the failsafe? Using my previous argument about the use of replicators in the holodeck might imply that the fewer safety protocols a person selects for a program, the more and more objects might be replicated instead of being holographic projections. Sure, you can't replicate a person, per se. That much is left to holographics. But bullets, chairs, tables, glass, nails, rocks...all might be replicated and then recycled when the program is able to be terminated. (Except for the parts with have been consumed...) By sealing someone inside during a system malfunction, the computer makes sure that the person has the ability to survive by giving them real things to live off of until the problem can be fixed. Also, nothing harmful can get into the ship by sealing the doors off. In this sense, the holodeck could have a very effective...if not annoying, failsafe.
