💤 Decision Fatigue:
Reduced quality of decisions with overload.
People find it harder to make rational decisions, as the total number of decisions that they've made increases.
e.g., after a whole day of making hard decisions at work, you may find it hard to decide what to eat for dinner (comparatively simple).
Conversion rates
The increasing difficulty of answering questions may lead people to avoid making them. This may manifest as churn.
Habits
It's harder to adopt a new habit if you're tired (physically or mentally). You seek defaults.
Input quality
Effort & motivation
Don't be afraid to split a 'user journey' into multiple sessions, and encourage the user to explore at their own pace. (i.e., don't teach them everything at once).
Set good default options, where possible.