विषयेन्द्रियसंयोगाद्यत्तदग्रेऽमृतोपमम्।परिणामे विषमिव तत्सुखं राजसं स्मृतम्॥
viṣayendriya-sanyogād yat tad agre ’mṛtopamampariṇāme viṣam iva tat sukhaṃ rājasaṃ smṛtam
Word by word
The verse says
The happiness that comes from the senses meeting what they want, like nectar at first and poison in the end: that is remembered as driven.
In plain words
The second kind is the same image, run backwards.
Nectar first. Poison after. And this is the one everybody already knows.
It is not condemned and it is not called false. The pleasure was real at the time. The verse only insists on telling you the rest of the sequence.
Where you've felt this · in relationships
You stay up far too late talking to someone you have just met and it is one of the best evenings you have had in a year. It was. The following three days are poor, you are short with people who did nothing, and a thing you had promised to do does not get done. Both halves belong to the same evening.
Going deeper
Describing the whole arc rather than just the peak is all this verse does, and it is more honest than either of the usual positions.
One position says such pleasures are wrong and should be refused. The verse does not say that. The other says enjoy them and do not think about afterwards, which requires you not to look. This says: it was nectar, and then it was poison, and both are true.
The trouble is structural rather than moral. Pleasure from the senses meeting their objects is real and it is also finite, and the finiteness arrives as a dip. Nothing has gone wrong when it does. That is the shape.
What changes if you accept this is not whether you have such evenings. It is that the dip stops being a surprise and stops being read as a sign that something is wrong with your life.