Our weekly "base"
"ליום השבת טוב להדות לה
For the day of Shabbos it is good to give thanks to Hashem. (Tehillim 92:1-2)
Isn't every day a good day to thank Hashem? It is especially appropriate to give thanks to Hashem on Shabbos because Shabbos is our weekly "base". It is our safehaven where the outside world cannot tag us and we can take leave of the chaotic concerns of the world for one day each week.