After her recent session with the word sort game, my sister got after me about conjunctions. It's not the coordinating ones she minds so much (FANBOYS have never bothered her), nor does she really seem put off by the correlative conjunctions, those two words with the ellipses in between. Subordinating conjunctions? Now that's another story. She doesn't like them. She's angry with them. She's frustrated and wonders why we need all of them in the first place. When she shared her issues with me, I tried to explain how we need subordinating conjunctions to begin subordinate clauses. Subordinate clauses can be annoying sometimes, sure, but without them, we can't have a sentence like: When you come home to visit, I will give you a piece of cake.
Just imagine that sentence without the subordinate clause When you come home to visit. If you were to hear the independent clause, I will give you a piece of cake, without the subordinate clause, you might wander around wondering when that piece of cake was going to come your way. You might approach strangers and ask them about it; increasingly frantic, you might skip meals on the off chance that the cake would arrive. You wouldn't be able to concentrate on anything but the promise, vague though it might be, of cake.
That's where the subordinating conjunction comes in. The word When introduces the subordinate clause, turning it into an adverb clause and providing the listener with the exact information necessary to make sense of the cake delivery issue. No confusion, no starvation, only delicious, delicious cake.
When you come home, of course.