I had the similar feeling like you. The space and greenery that are more natural give that sudden relief and stress-free feeiling.
So sad. Everytime when I drive on the bridge towards MY customs (Tuas side), my heart feel so light and 'cheng' once start seeing those green mangroves stretching few kms along the blue straits and all those stress reduced immediately.
Returning to SG, stress starts to pile up again. Haha!