Heh, on the occasions that I actually do decide to take food home, I almost always leave it there too. 
Sorry, rereading my previous post, I really sounded like an ass. :smack: Thanks to Lissa and Wendall for responding politely, which is more than I deserved.
I am fine with taking home leftovers that can be made use of. But often I see people order too much and then take home leftovers, or order something, move it arround the plate all meal, then take it home as leftovers, which both seem silly to me.
The time I especially take left overs is for Thai soup and pizas. For both a larger portion costs very little extra, and if you get the larger portion and take half as leftovers they both heat up again well. I tend to avoid restaurants that serve overly large portions, they just tempt you to overeat, and it is rare that a really good restaurant has over large portions, so what you take home with you is rarely worthwhile.
I regularly take leftovers home. We tend to go out to dinner on friday nights and I like having something ready to go for lunch saturday. What I’ve started doing is dividing my meal in half when I get it and putting it in a to go box. Makes dieting a little easier. 
Depending on what part of town I’m in I’ll get the leftovers and just hand them to a homeless guy that might be standing outside the restraunt.
If i’m in the nicer part of town I don’t bother because as others have said: I probably won’t eat them and why stink up my truck?
(BTW, If anybody’s planing to use my idea of handing off the leftovers to a homeless guy; be prepared to be told to “fuck off!” a couple of times. I’m not sure I get this personaly)