Exercise gives you energy. It sounds counterintuitive, but it's true. Well, unless you run, for example, a 24-hour race. Then you're probably beat. And if you run intervals. That makes you tired. And if you cycle for 50 km. ANYWAY. My point is that exercise always gives me a buzz, the kind of mental strength that I need in order to do boring stuff. Like vacuum cleaning and packing.
The plank. Crunches. Toe lifts, hip lifts, arm dips, I did a full body session and watched the sweat form like pearls on me. An intense hour without breaks that left me pumped. A shower later I felt like a new person. Love exercising. Love it.