You've seen me several times as you pass by
But never acknowledged me. I wonder why...
I'm surrounded by fellow friends
Half-way between us our link ends.
To your right, I'm not much to see,
To your left I gaze intently.
It's quiet on this side, except when you are near
Half-way up, it's my voice you will hear
Only once, maybe twice...
I only mean to surprise
Tick-tock, creaking floor
Remember my path, you'll pass once more.
What am I?