Why do you think the OBE experience is scary at first?

[xAmberxLeahx]

When someone is about to have an OBE, why do they hear scary sounds or see disturbing figures?

[CFTraveler]

This is explained in the Ad Pedia in the 'Early RTZ experiences'. Or look at the stickied topic "Your First Conscious Projection"
viewtopic.php?f=7&t=7304&p=55885#p55885
Which goes through the symptoms and the possible causes. As to why they're scary? Because they are not the sort of things that happen in everyday waking reality. We tend to fear the unknown or different. And this can be considered very different.