I, not events, have the power to make me happy or unhappy today. I can choose which it shall be. Yesterday is... — Groucho Marx

I, not events, have the power to make me happy or unhappy today. I can choose which it shall be. Yesterday is dead, tomorrow hasn't arrived yet. I have just one day, today, and I'm going to be happy in it.

Author: Groucho Marx

Insight: There's something quietly radical about this idea, especially when you consider how much mental energy we spend replaying yesterday or catastrophizing about tomorrow. We treat our mood like the weather—something that happens to us—when actually we're making constant tiny choices about where to point our attention. The person who cuts you off in traffic, the email that stings, the plan that falls through: these are real events, but your emotional response isn't automatic. There's a gap between what happens and how you feel about it, and that gap is where your actual power lives. What makes this stick is that it doesn't require denying real problems or faking happiness. It's not about pretending bad things didn't happen. It's about recognizing that spending today being miserable won't change yesterday, and it definitely won't improve tomorrow. You can take yesterday's lesson and move on. You can prepare for tomorrow if needed. But the only day you actually get to live is the one in front of you right now, and how you experience it depends partly on what you choose to focus on. The non-obvious part? This isn't actually easy, and that's okay. It's a practice, not a switch you flip. But each time you catch yourself spiraling and deliberately choose differently, you're building a real skill. That's the actual power—not that happiness is instant or that choosing once solves everything, but that you get to practice choosing again today.