Star Trek: 10 Disastrous USS Voyager First Contacts
2. Most Storms Don't Rain Nanoprobes
Voyager's journey home through the Delta Quadrant had a profound impact on species they never even made official first contact with. The repercussions of seeing Voyager in the wing mirror were so enormous for Species 116 that we only know them by their Borg designation. One surviving member caught up with Captain Janeway a year or so later for revenge. Best served assimilated.
Arturis held Voyager — and Janeway in particular — responsible for the assimilation of his people, who were counting on Species 8472 to turn the tide in the war against the Borg — the "storm on the horizon". The bipedal universal translator (who definitely needed a new shirt) planned to lure Voyager's crew to his fancy slipstream ship and deliver them to the Collective.
As Arturis put it, Janeway couldn't see "past the bow of [her] own ship" when she made her deal with the devil to fight 8472. That decision, far from being unanimous even amongst Janeway's senior staff, has divided fans ever since. You might think the captain had little option but to fight those who wanted to purge the galaxy of life. Janeway could have equally turned the ship about and let the Prime Directive, and some wishful thinking, do the rest.