=> IT to business interaction   There is no "the business".  If you ask for "the business" there is no one person to come tell you everything.   In most case, when the business comes to you, they are really wanting a work-around.  "Add this column to this report". "Allow me to sort by this".  These are not requirements, they are work-arounds.  For the most part, you don't want to be building work-arounds.   You need a product owner, requirements engineer or whatever who the business will listen to and can push back.   Helpful in this phase is to do rapid prototyping.   Well-formed estimates include a degree of confidence that the project will be done between a T1 and T2 time period.  This assumes:

- Formed team (already worked together)
- Team familiar with tech
- Team not working on anything else
 Developers are familiar with the concept of being in the "flow" where we're at our most productive, most concentrated.  We need to know our high-energy periods and not waste them.  After 2-3 hours of this, however, we need a break, we run out of energy.  During the down times, we can work on rapid prototyping work, project planning, etc.