What is so special about besamim [spices] that they are used for havdalah?
The Shulchan Aruch writes that it was ordained to recite a blessing on spices after the Sabbath as part of havdalah. We will explore 3 reasons below:
1. The Sabbath is a day in which we experience spiritual delights in a physical manner. As such, the soul (which is a spiritual entity) grieves over the departure of Sabbath. To restore our soul (or neshama), we awaken it with the joy imparted by fragrant spices (based on Maimonides, Laws of Shabbos 29:29).
2. Let’s face it… the Sabbath is a healthy departure from the daily grind of making a living, and sometimes we aren’t looking forward to the week ahead. As such, the fragrances alleviate the sadness of the heart when thinking about the upcoming week (Sefer HaPardes p. 26).
3. Finally, on the Sabbath we have access to a neshama yeseira (an additional soul). As such, the spices are to comfort us from the loss of the additional soul which we receive on Shabbos (Tosafos, Beitzah 33b).