Add events (client followups, reminders, etc) using the Calendar section (WITHIN a client's profile) as reminders that get added to my Google calendar, but that DO NOT send a Calendar invitation to the client.
This is SEPARATE from their "TASKS" feature, which I find useless, and do not get added directly to my calendar.
STEPS:
  1. Within the Client's Appointment section, Select "ADD TASK"
  2. Select my dedicated "TASK CALENDAR" that add the item to my Google Calendar only.
Also would be good idea to add/invite another person within my organization to the Task, so that it also goes on THEIR Google calendar.