i've always been amazed when someone pulls off a poem with less than twenty words... and a lot of the time they don't manage. so congrats, because this is wonderful.
Awesome. There are a lot of cases when a kiss is only the means to something else ... so much so that, as you have implied here, sometimes the value in that kiss itself is lost. Great insight - simplicity is often the best tool to draw contemplation!
My only suggestion would be to break the lines slightly differently in the middle for a bit more rhythmic consistency:
When a kiss
Is not the
End
But merely
the means to
an End
With that being said, I do realize that your line style puts more emphasis on the word 'means', which may be more important to you than the rhythm in that case. But it is worth considering!