As it turns out, based on a series of experiments conducted at the University of Minnesota (USA), researchers have found that when people consume certain products in tanden - such as nacho chips and salsa sauce - they enjoy the products more if the brands match. So if you were to snack on, say, a bag of Tostitos nacho chips and Old El Paso salsa sauce while watching a televised football game, you wouldn't enjoy the snack as much as had the chips and sauce brands matched (such as Tostitos chips and sauce or Old El Paso chips and sauce). Similarly, we might imagine that you would say your burger was tastier had the ketchup and pickles brands matched.
As to why matching brand labels lead to greater enjoyment, the researchers suggest that they encourage consumers "to believe that the products were tested and designed to go well together."
There is no universal answer to which brand a consumer likes the most. The brand a consumer prefers for a particular product depends on the brand of other products with which it is being combined. A company that offers products that are consumed together will have an advantage over other rival brands that do not offer both individual products, since consumers will want to have matching brands.
So now you know why many of the recipes - there I go again - on food packages tend to include certain ingredients that bear the same brand as the purchased item - often obscure or hard-to-find ingredients that only the brand offers.
One final nachos point - if you find the Tostitos logo particularly memorable or likeable, it could be because of the embedded image of two happy consumers (well, I don't really know how happy they are) - the two 't's in the center of the brand name - holding a giant nacho chip over a bowl of salsa sauce - the dotted part of the letter 'i'. For the sake of closure (although this example is more consistent with the perceptual principle of figure-ground than closure) let's just assume the chip and salsa are both Tostitos, and that the consumers are happy.