Analysis:
This quatrain by Saadi Shirazi is a playful and somewhat enigmatic exploration of love, desire, and disappointment. Let's break down the lines:

Line 1: گفتم شب وصل و روز تعطیل آمد

"I said, 'The night of union and the day of leisure have arrived,'"
The speaker is expressing anticipation for a romantic encounter. The "night of union" and "day of leisure" suggest a time of intimacy and relaxation.

Line 2: کان شوخ دوان دوان به تعجیل آمد

"That playful one has come running in haste."
The speaker is excited about the arrival of their beloved, whom they describe as "playful".

Line 3: گفتم که نمی‌نهی رخی بر رخ من

"I said, 'Won't you turn your face towards me?'"
The speaker is asking for the beloved's attention, hoping for a romantic encounter.

Line 4: گفتا برو ابلهی مکن پیل آمد

"He said, 'Go away, you fool, don't be foolish, an elephant has arrived.'"
The beloved's response is unexpected and seemingly dismissive. The image of an elephant is used metaphorically, possibly to suggest a powerful or overwhelming force that has distracted their attention.

Deeper Meaning:
This quatrain can be interpreted in several ways:

Unfulfilled desire: The speaker's hopes for a romantic encounter are dashed, leaving them feeling foolish.
A metaphor for life's distractions: The elephant could symbolize the many distractions and challenges that life throws our way, preventing us from achieving our desires.
A playful tease: The beloved's response could be a playful tease, meant to heighten the speaker's desire.

This quatrain is a short, evocative exploration of the complexities of love and desire. The unexpected twist at the end leaves the reader pondering the true meaning of the beloved's words and the nature of their relationship.