A cog in the machine/wheel
Definition 1 of 1
Pro Tip 1/3Feeling Unimportant
Emphasizes feeling undervalued and replaceable within a big system. 
With all the automated processes, I'm just a cog in the machine at the factory.
Pro Tip 2/3Lack of Influence
Highlights lack of power to effect change or make significant decisions. 
You're a cog in the wheel there; you won't be able to change their policy.
Pro Tip 3/3Organizational Humility
Can express awareness of one's modest role or position in a complex structure. 
As interns, we're just cogs in the wheel, but we're learning a lot.