What does it mean that internal triggers versus external triggers?

Internal triggers are thoughts and feelings — external triggers are events and cues.

Example: You sit down at your desk Monday morning and open Twitter before doing anything else. No notification pulled you there. No calendar event said 'browse Twitter.' A vague feeling — restlessness, avoidance of the first hard task, low-grade anxiety about the week ahead — fired the behavior automatically. That's an internal trigger. Now compare: your phone buzzes with a Slack message and you switch apps immediately. That's an external trigger. Same behavior (context-switching), completely different origin. Until you can tell the difference, you can't design for either one.

Try this: For one full workday, log every behavior change you notice — every time you switch tasks, open an app, stand up, reach for food, or check your phone. Next to each entry, write I (internal) or E (external). Internal: the impulse came from a feeling, thought, or physical sensation with no outside prompt. External: something in your environment initiated it — a sound, a notification, a person walking by, a time on the clock. At the end of the day, count the ratio. Most people discover their internal triggers outnumber external ones by at least 2:1.