system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Trek] Why do most Federation ships have a neck?

The Star Trek Federation ship has an iconic look. A saucer, a long thin neck, a core, and two huge engines. I am not a professional engineer, but the neck connecting the saucer to the core seems like it would be a structural weak point. Especially when newer designs (Voyager) and some of the earliest designs (the First Enterprise) do NOT have this feature, AND when you also consider that no other civilization seems to have copied this design. 

So why would the Federation build their ships this way?
gpt
The hulls of most starships are reinforced with force fields called structural integrity fields. While its engines are running, no part of a ship is a structural weak point. The typical shape of a federation or Klingon ship is designed for optimal warp geometry. To put it another way it's "aerodynamic" for the fabric of space-time.