Also some forms of shapeshifting can be horrifying. In some kinds of shapeshifting, you have to be able to visualize every minute detail of the form you're shifting into. Imagine getting shapeshifting powers and shifting into another form. Then when you want to shift back, you realize you don't actually have a "default form." You can shift forms as often as you want, but you have to picture and visualize every minute detail. Your original form is now lost forever. Remember Odo from Deep Space 9? His form was roughly humanoid but clearly not natural. He had to consciously control every minute detail of his face.

Imagine trying to paint a photo-realistic painting of yourself. That's a fraction of the level of detail you'll need to capture every detail of the forms you're changing into, including your original one. Even your original form is now lost, replaced with whatever half-remembered remnant you can cobble together with your mind.