My 18-month-old golden has perfect recall at home but the second we're at the park she ignores me completely. I've tried treats but she doesn't care. What gives

Your recall isn't perfect at home — it's untested. At home there's nothing more interesting than you. At the park there's everything. You built the skill in easy mode and deployed it in hard mode. That's the gap. Start over. In your yard or a quiet street, call her from 10 feet away while she's mildly distracted (sniffing, looking elsewhere). When she comes, give her something better than what she left — a high-value treat or a game of tug. Repeat 20 times across three days. Then add distance. Then add distractions: practice near (not in) the park, on a long line so she can't rehearse ignoring you. Call her once. If she doesn't come within 3 seconds, reel her in with the line and give her the reward anyway. You're teaching the pattern, not testing compliance. After 40-50 successful reps in medium-distraction environments, try the park on-leash first. Off-leash recall at a dog park is the final exam. You're trying to give it in week one.