When Golgari Thug dies, it and Dross Harvester trigger.
Resolve the Golgari Thug trigger, putting it from your graveyard onto the top of your library.
Resolve the Dross Harvester trigger, causing you to gain 2 life.
Resolve the Woe Strider ability.
Cast Golgari Thug from the top of your library by paying 2 life.
Repeat.
This loop uses Woe Strider to sacrifice Golgari Thug over and over, feeding your graveyard while keeping your life total safely buffered by Dross Harvester's life gain whenever a creature dies. Because Bolas's Citadel lets you cast spells straight from the top of your library by paying life instead of mana, you can immediately replay the Golgari Thug that its own death trigger puts back on top of your library. This creates a self-sustaining engine that fuels massive storm counts and endless triggers, turning your sacrifices into a relentless cascade of value.