One of my favorite moments happened after my C#-based back-end company was acquired by an all-[FASTER LANGUAGE] company. We had to connect our platforms and hit a shared performance goal of supporting 1 billion events/month, which amounted to something like (IIRC) 380 per second. Our platform hit that mark running on 3 server setup w/2 Amazon Medium FE servers and a SQL backend. The other company's bits choked at 10 per second, running on roughly 50x the infra.
Poorly written and architected code is a bigger drag than the specific language in many cases.
At the risk of setting up a strawman for people to punch down, try comparing how easy it is to do the equivalent of something like this in C#, and feel free to use as much IDE magic as you'd like:
x = [t[1] for t in enumerate(range(1, 50, 4)) if t[0] % 3 == 0][2:]
There's a million other examples I could write here, but I'm hoping that one-liner will be sufficient for illustration purposes.
As the sister post says: Go is in the same class as C# only it's a bit verbose/ugly in comparison but it compiles to native machine code..