Multiple axes:

• Degree of uncertainty and magnitude of duration of the length of time before it will be 'safe'.
• Degree of effort involved in avoidance (temporarily holding off on reading a specific email vs. actively avoiding certain knowledge and filtering all information for a long and unspecified duration).
• Severity of consequences (delayed or somewhat sub-standard performance on a near term project deadline vs. fundamental change or damage to your core values)
• Scope of filtering (avoiding detailed contents of a specific email with a known and clearly delineated area of significance vs. general avoidance of whole areas of knowledge where you may not even have a good idea of what knowledge you may be missing out on).
• Mental resources emphasized (short term attentional resources vs. deeply considered core beliefs and modes of thought and high level knowledge and understanding).