Cons: you are controlled by officials that are remote from you, disconnected from your land and people, indifferent or more likely hostile towards your culture and values, and beyond your reach. It will always lead to policy aimed at bringing everything down to the lowest common denominator. There are zero pros from the perspective of the governed.

Edit: also, odd sub to stick this in.

Pro: Wholly standardized units of measure.

Con: Literally everything else.

Im not sure if this question belongs in this sub the way it was framed but I'll allow it.

Cons:

-Too many different languages and cultures/sub cultures and religions

-It is being constructed by devious pedophiles and psychopaths (same shit really)

-it's hard enough to run a single country even with the best leaders. Most people are a hairline above retarded

Pros:

You cannot have an original thought or don't act like they'd approve of.

First, you need to understand if the government represents you or controls you. Typically there are no benefits to a single government because they're disconnected from localities.

Pros: If you are part of that government your subjects have nowhere to escape to.

Cons: Every single place on Earth will start be melded into a uniform sludge. Same stupid rules, same stupid culture, same 75% tax. No better place to move to if you don't like it, because every place is the same. You're practically living in hell.

There are no pros.

An understanding of what some think are pros is needed to know how to counteract the progression of and, at worse, steer it in a proper direction. I say that because I personally believe that one world control is inevitable. When and how it happens is what can be steered.