Yeah, I think the key to the depressive-behavior thing is that the reason for going out is irrational. If you're legitimately staying in because it's cold, that's reasonable, albeit maybe a little wussy. But if you're using the cold as an excuse not to go out because the thought of going out plunges you into a fit of fear or despair, or you're not even lying to yourself anymore and just admit that you're not going out because of fear/despair, that's depressive.
Belatedly -- thanks for the cans, guys. To explain my statement above: I'm the kind of person who always feels uncomfortable about making conversation in an altered neurochemical state that consists entirely of "hey, I'm in an altered neurochemical state!" Going around being depressed and only talking about my depression strikes me as the equivalent of those people who get drunk and loudly proclaim how drunk they are, except that I am rather less likely to wake up the next morning non-depressed and vaguely ashamed. (Well, okay, I'm likely to wake up ashamed, but, y'know.) I mean... to be blunt, it's on the same level as "dude, I am so drunk!" in that nobody really cares, and it is also frequently as obvious. When I'm eating one meal a day of whatever-comes-to-mind at an essentially random time, only sleeping between the hours of 10 AM and 6 PM, and leaving the apartment only after great deliberation, saying I'm depressed almost defines redundancy. (At least, it does to me. The other awkward thing is that, after a lifetime of being an Emotionally Stable Person, I face a general reaction of "why didn't you tell me?!" the instant I say anything. It's not that I don't trust you, Parents or High-School Best Friend or Roommate or Whoever I'm Telling Now, it's the fact that admitting this makes me feel like I'm going to throw up.)
... Well, that was hypocritical, huh? The other problem with talking about depression: you inevitably overshare. If one has to overshare about current neurochemical states, I'd rather it be about positive ones. "I am so drunk!" is almost okay if the drunk person is basically happy, and one of the best conversations I ever had with a college friend of mine took place after, after years of sexual frustration, he finally got laid and as a result was effusively happy about everything. It's fun to talk about how suddenly colors are brighter and the world contains an infinite capacity for joy.
So, how about that comic with the retarded otter? I'm a fan!