In "Sunshine on Scotland Street," Alexander McCall Smith highlights the common tendency to believe that happiness lies in different circumstances or locations, which can lead to dissatisfaction with our current lives. This mindset preoccupies our thoughts and distracts us from appreciating the present moment and surroundings. We often envision a more fulfilling existence elsewhere, thinking it will bring us joy and contentment.

The key message of this quote is the importance of nurturing happiness in the present rather than longing for an idealized future or alternative life. By focusing on what we have and cultivating gratitude, we can discover deeper happiness in our current situations. The challenge is to shift our perspective and actively seek joy in our present, rather than chasing it in hypothetical scenarios.