These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Lost Forever: Many items found only in single-visit areas in Agents.
Subverted— anything you miss in one of those areas, you'll get as a dispatch mission reward later on.
Surprisingly Improved Sequel: One can't really stress this enough, there was virtually nothing to do in the original game. Every additional game would include new and better plots and adventures and flat out stuff to do.
That One Sidequest: A lot of players aren't exactly fans of repairing and analyzing tasks in Agents.