Preventing over-optimization of clicks in a push ad system means focusing on user value, not just raw click-through performance metrics. Tracking only clicks can push algorithms to spam users, so we also measure retention, dismissals, and long-term engagement quality. Adding guardrails like frequency caps, diversity constraints, and satisfaction signals helps balance optimization so ads don't become annoying or repetitive. A/B testing should include user fatigue metrics and opt-out rates, not just CTR improvements across segments over time.