If you could instantly become an expert in any subject, what would it be?

That's a tough one! If I could instantly become an expert, I'd probably choose something that blends knowledge with practical impact, like sustainable energy technologies. Mastering that field could help address major global challenges, from climate change to energy access. Plus, it's a subject with a lot of room for innovation and creativity. What about you—if you could become an expert in anything, what would it be?