The Transition phase of deep cognitive work is often the most critical and difficult stage
When you start, your brain is still dealing with Attention Residue, lingering thoughts from your last email or conversation. The term Attention Residue was coined by Dr. Sophie Leroy in her seminal paper, “Why Is It So Hard to Do My Work? The Challenge of Attention Residue when Switching Between Work Tasks.”
So the work is challenging and your brain protests. To reach the next stage, you must stay put! Once you settle in past the twenty minutes or so, the friction begins to dissipate. You will successfully load the variables of the problem into your working memory.
It takes quite some time just to settle in especially with challenging problems or tasks of different contexts.