Texture matters, too. Dark corn syrup is slippery and thin, perfect for pouring and swirling. Molasses is thicker, slower, and clings to the spoon like it owns it. Because corn syrup is less sweet than white sugar, it gives you that gooey chewiness without overwhelming your teeth.
Molasses, on the other hand, is less sweet than corn syrup but stronger in personality. It’s the loud friend at the party; corn syrup is the one who just nods and refills your drink. Substituting the wrong one is like asking the loud friend to be quiet—it just doesn’t work.