What is the difference between personal observation of a motor vehicle accident and personal witnessing of the accident?

In a footnote in Ochoa v. Superior Court (1985) 39 Cal.3d 159, 216 Cal.Rptr. 661, 703 P.2d 1, quoted with approval in Thing, the court explained why contemporaneous observation of an accident merits different treatment: "[A] distinction between distress caused by personal observation of the injury and by hearing of the tragedy from another is justified because compensation should be limited to abnormal life experiences which cause emotional distress. While receiving news that a loved one has been injured or has died may cause emotional distress, it is the type of experience for which in a general way one is prepared, an experience which is common. By contrast few persons are forced to witness the death or injury of a loved one or to suddenly come upon the scene without warning in situations where tortious conduct is involved. In the present case, for example, while it is common to visit a loved one in a hospital and to be distressed by the loved one's pain and suffering, it is highly uncommon to witness the apparent neglect of the patient's immediate medical needs by medical personnel." (Id. at p. 165, fn. 6, 216 Cal.Rptr. 661, 703 P.2d 1.)