When the Great Bird of the Galaxy, Gene Roddenberry, created Star Trek, he envisioned a utopian future characterized by what he believed humanity could achieve. Star Trek: The Original Series, its animated offshoot and Star Trek: The Next Generation were the Platonic ideal of that future. He famously instituted what writers called "the Roddenberry box," which said conflict in the series couldn't come from petty or personal differences among the crew. He wanted his Starfleet heroes to be as perfect as possible. Star Trek: Deep Space Nine didn't really depart from this formula, though many of the characters were not Starfleet.
Source：https://www.cbr.com/star-trek-deep-space-nine-still-relevant/
