Strip your opponent of that Crashing Drawbridge, Soulless Jailer, or Electrostatic Field which are outside of bolt range but might not be your preferred targets for targeted removal either
For example, Annihilate will be card advantage if it resolves normally targeting a creature an opponent controlsyou lose one card from your hand but you also draw a card, for a net gain of zero cards, and your opponent loses one card, so you're up one card relative to them
In short, the flavor text is just a clue to help you figure out the card
The real power of cards like Grief comes when you combine it with blink effects like Ephemerate, which allow you to get two ETB triggers and keep the creature in play
If there are two Primal Vigors on the battlefield, the number of tokens or +1/+1 counters is four times the original number