I do think that if you bring something, it's borderline rude to take it back home with you. I've totally done it but only with people I know won't be upset.
We have friends that, if there is anything left of what they bring for a party, they always take it home. I've seen them take the two remaining hot dog buns and half a bag of Doritos home after a BBQ.
oooh, these are my fave winter sheets. Smonster, if you can find them on discount, might be a nice gift as long as he's not a super-hot sleeper. They are very, very warm and snuggly. [link]
[eta: yes, polyester, but sure as heck don't feel like it.]
Oh, I hadn't thought of people bringing dishes. My family usually hosts Rosh Hashanah and Thanksgiving, and we cook everything. Guests just bring dessert. The only times I can remember guests bringing main dishes or sides were when people had special dietary needs. (We've actually got enough people with weird food rules that my mom and sister and I can figure out how to adapt pretty much any meal to pretty much any diet, but there are a few cousins who like to be sure and bring their own stuff.)
I'll take my dishes home if I bring something, but I always leave the food with the host/hostess unless they ask me or offer me leftovers.
I think it's rude to take home what you bring unless you're asked to take it home with you.
In some situations, if everyone brings a dish, leftovers can be overwhelming so I try to send stuff home with people.
And now the waiting begins.... Daniel's best case scenario for getting home from work today would have been about half an hour ago. I've got caramelized pears warm on the stove, ready for him.
I plan on taking home any physical dish i bring (like, the metal or glass container) but consider being gifted with leftovers a treat based mostly on how many guests are present and how many takeway containers the host has on hand. (edited to correct my innapropriate use of lower case "i")
Now that I think about it, I really can't imagine the logistics of trying to plan a holiday dinner where everybody brings stuff to be eaten during the main course. We've got enough trouble just doing that with dessert and making sure that everybody will have something to eat, since we've got one vegan, one diabetic, one gluten- and dairy-allergic, and one who doesn't eat fruit. (The dessert solution to this situation, if you want to be relatively simple about it, is to have one bowl of berries and one vegan chocolate cake, with some regular whipped cream and a can of vegan whipped cream for the berries. If you start overthinking it, you end up with five desserts.)
I think it's rude to take home what you bring unless you're asked to take it home with you.
I was raised that way too, but since most of our guests who brought sides to Thanksgiving did exactly that, I decided it must be a personal thing. We had 18 friends for Thanksgiving this year, and everyone brought something. I would have happily sent people home with leftovers bit didn't have enough take home containers to really offer.