Power

Besides the tools in your work space (and the voltage they draw), you won't have a whole ton of power to throw around in this career. Pardon the expression, but in the machine shop, you're often just another cog in the, ahem, machine. 

You'll be doing a small, repetitive task dictated by the engineers who designed the product you're helping to create. You won't have a lot of say in how it gets done, when it must get done, or the function it serves—you're just there to make sure your part gets completed.

One could argue that machinists do hold a certain kind of power, even if it's not exactly autonomous: the small piece of the final product for which you are responsible must be perfect. Consider the bolts from the first section—if those bolts aren't fabricated to the exact, and we mean exact, specifications as dictated by the engineer in charge, all sorts of things could go wrong. 

Production for the bulldozers could take longer than expected, costing the company lots of money. Even worse, faulty bolts could present serious safety hazards if they don't fit correctly or wear out too easily (source). You're in charge of preventing that.