In relationships, I tend to be the rational possibility-oriented one. I tend to focus on Ne in terms of how I behave ... flexy, laid-back, non-committal, wanting to play things out and explore rather than nail stuff in... but once I'm serious or have decided that it's what I want and that it all "makes sense" to invest in, then I'm more willing to nail stuff in place.
If big-picture I see major issues/conflicts with underlying perceptions of reality, then I'm going to see the relationship as fundamentally doomed. Due to my flexiness, I can hold that thought in mind and still "give it a shot" for a bit just to see if reality follows theory, but typically the conflicts I foresaw are pervasive and unfixable. I don't allow the relationship to obfuscate things; if the topic comes up, or I feel like the other person is making bad assumptions, I'll be the "downer" and clarify the problems I see.
Love ya, Jeno, but I couldn't quite do what you did... I like it to be more organic, although I definitely like to rationally "negotiate the agreement" and spell it all out at various times so we're both on the same page. Maybe this is less a difference in thinking and more just a difference in overt response; I like my flex and to be easy-going, and so I talk in more casual ways even if I think structuredly.
I didn't realize until later in life that there are many people who don't need to or don't want to or can't even articulate the structure of the relationship, whereas I naturally think that way...