When an iceberg collapses, sending its freezing shards into the sea below, it can look pretty and all ooooooh-y and aaaaaaah-y. Except if you're up close, and then you realize that those shards actually generate humongous, potentially boat-flipping waves that could ruin your whole day.
By dumping you into super-cold water. Where you could drown. Or, you know, freeze.
So maybe you can understand why when you see one collapsing, an experienced boater will scream at you to gun the engine and get the hell out of there.