Why people dislike global variables so much while I find them so convenient?

[forkit]

On Tuesday, 25 January 2022 at 09:53:25 UTC, rempas wrote:
>
> So can someone make examples about how global variables can 
> mess me up. I know that probably everyone here has more 
> personal experience than me so I really want to learn why 
> global variables are considered so harmful.

// ---

module test;
import std;

int x = 0;

void main()
{
     writeln(foo);
}

int foo()
{
     int x = 10;

     if(x) // ooh. you sure this was your intention??
         return x;
     else
         return .x;
}

// ---