lingering look

The Look
Strephon kissed me in the spring,
Robin in the fall,
But Colin only looked at me
And never kissed at all.

Strephon's kiss was lost in jest,
Robin's lost in play,
But the kiss in Colin's eyes
Haunts me night and day.
-- Sara Teasdale

Isn't it weird that only a look remained while the kisses weren't?
One thing can be remembered if it has a signifaicant value to a person. In the poem, the kisses by Strephon and Robin maybe were just flings, or maybe just lust.
Each person looks for a someone that would be the one who would complement him/her. As you see, each person looks for someone that he/she would love who would love him/her back.
A kiss would mean 'love' to some people. But sometimes, it would just mean lust. But Colin's look was so full of love that it remained forever in the speaker.
In life, even the littlest thing may sometimes have the biggest effect. Sometimes, a single word may be remembered forever by a person because of its big effect. In the poem, Colin's gaze was so full of passion, so full of life. Or maybe Colin is someone who the speaker has unknowingly loved.

Love works in baffling ways. We may not notice it, we could have been loving someone without us even knowing it. I know that because I did, I really did. When I first became aware of loving that special someone, I felt light. I felt that I was on cloud nine. If you have loved or currently loving someone, you would agree with me a hundred percent. To be in love means happiness if you only look on the bright side. The not so bright side is the times of obstacles. But when the two people team up and work together, no obstacle in the world can break the love they share.

I am a little bit moving away from the topic back there. So, I will go back to the poem.

Strephon and Robin were two different people. Since the poem states that Strephon kissed the speaker in spring and Robin in the fall, it can be inferred that she 'loved' them at different times.

Why did I enclosed the word 'loved' in quotation marks? This is my reason:

Jest and play are synonymous. Both are related to humor, laughter, or mockery of some sort. Both have a definition opposed to seriousness. That means that the relationships of the speaker
with Strephon and Robin are just flings. That is the reason why Strephon's kiss was lost in jest and Robin's lost in play.

On the other hand, Colin's look was meant more than a kiss from flings. When noticing that Colin was looking at her, the speaker would have probably looked at Colin's eyes for Colin's look to haunt her night and day. An eye-to-eye contact shows more what words can say. It shows compassion by both parties.

A different reason for Colin's haunting look could be that Colin was someone to the speaker in the past. Colin could have been her special someone would she broke up with and regretted what she had done because she still loved him through the years.