There is nothing quite like the dynamic that takes place when two committed actors are fully engaged with one another. The moment to moment work is where we listen with our entire instrument, not just hearing what is been said so that we know when it is our turn to speak again, but feeling it and letting it settle in us and allowing this to inform our response. No matter how prepared we are or single-minded our objective is, if the moment to moment exchange isn't taking place on an honest level then what we are left with is two actors in two completely different scenes.
When I ask you to take your time, don't worry about pacing. Really hear what is being communicated, see where that wants to settle with you and how it makes you feel (what feelings/emotions are triggered and what thought processes take place). It is usually because we have a tendency to plow through a script in a preconceived fashion that we end up skipping past invaluable moments that are the life line and essence of the characters we take on.
Yes, there are technical requirements that also come into play, setting the tone and feel of any given piece, but until we truly allow ourselves to live the moments fully then what we will end up doing is going through the motions and developing bad habits.
The moment to moment work is where the story comes alive. It is a spontaneous and organic process that requires an openness to be heard and to hear.