When John arrived at his office, he was preoccupied with thoughts of the product

When John arrived at his office, he was preoccupied with thoughts of the productivity report he had not yet completed for his immediate supervisor. Today, he thought, there can be no distractions or superseding priorities. The report must get done, or else.
No sooner did he get settled at his desk when a phone call came from an important client. He politely attempted to keep the conversation at a minimum, but everyone knows how important clients can monopolize time. As he hung up the phone, John noticed Sam in the doorway. Sam had a personal problem, and because John wanted to be a good manager, he felt he could not put Sam off until later. His conference with Sam was abruptly disrupted by a controller who stormed in and insisted that he just had to have some information for his budget proposal, and he needed it before lunch.
To his dismay, John found that the day disappeared in meetings, phone calls, emails, personnel problems, and unexpected visitors. Before he realized it, 5 p.m. rolled around, and besides a grumbling stomach from missing lunch, John still had not accomplished the one important priority he had set for himself that morning. The report was still not finished. There’s just not enough time in the day, he groaned.
Questions:
Can you realistically expect to control things like John faced?
What do we know about John’s habit patterns?
What would you suggest that John do to improve things?
Would a “quiet time be a good idea for John? If so, how could he make it happen?
https://managementhelp.org/personalproductivity/time-stress-management.htm