Exercise. A long bike ride somewhere new is best. Or push my limits, like go ride a couple hundred miles just because and do it in a loop where I don’t see the same thing twice. Take a selfie somewhere unexpected and post it somewhere as bragging rights. One day, when you can no longer do those things, the pictures will matter to you a whole whole lot when all you can do is a short routine. If you are at all able, use the lows as a catalyst to plant your flag and push your boundaries. This will absolutely invert these moments in time where, with age, these memories will become high points in your life through the rose tinted glasses of hindsight. You’ll never recall the reason you felt low but you will own your remarkable accomplishments for life. Over time your past lows stop compounding at the edge of memory. If you make such endeavors a part of your identity, lows may totally invert and become the motivation to get out and ride. Most cyclist roadies I know are driven by this mechanism. Exercise is the largest and most readily available, self accessible source of endorphins. Ultimately we are all chemistry, so don’t hesitate to alter the reactions experiment with better ingredients.