As above. Not conflict like people necessarily in conflict with each other, but conflict in something happening - internal, external, in opposition to goals, etc.
Even if it's not obvious in the scene that what's going on is conflict, everything should drive the plot forward.
Like, for instance, from a fluffy thing - in a Shopaholic novel, the character can be happy and buy the perfect single thing that sends her on a wonderful date with her perfect bf and it seems great.
However, that's conflict - a. (internal) she shouldn't be shopping to begin with, b. (foreshadowing) later in the book, it will cause a problem one way or another, c. that perfect bf/date will turn out to be the harbinger of a problem or something she shouldn't have been doing because x, y, or z, thus there will be an issue.
It's all, even if it's lovely and happy at the moment, someplace either adding to the up side of the roller coaster or solving the problem on the down side - moving the plot, no matter which way. Does that make sense? I'm kind of mixing metaphors all over the place, heh.