The Fear of Conveying 'Thanks'

The only feeling
I am sensitive to at times
[When someone says or does something,
Making me very, very happy indeed,]
Is the spread-eagled numbness
Gagging my thoughts.
Happy thoughts of gratitude,
Weren't those meant to be?

I smile at the person
Straining my eyes, 
So as to not let them blink 
As they look on at me, with a word of love.
While I,
Stoop within endlessly 
To pull out a few thoughts,
Clearing my throat
Hoping for a sentence to follow next,
However mindless;
Eventually falling silent.
I'd like them to know 
That's not me being cynically laconic, no.

I think -
The memories,
Charred with inadvertent retrospection
Wake up from their insomniac slumber
At such moments,
Rush to claim their place,
Smearing dust on the present.

P.S. Have you ever shied away from saying a thank you to someone who made your day?
It's not shyness being discussed here, of course. It's a constricted state of mind, feeling stifled enough to stop you from thinking at all, making you restless enough, though.