I do enjoy transformations, and I have one personal rule when it comes to it. While many have it permanently if they like it or not my rule is that there has to be a way to undo or forbid the transformation in the first place. This includes a time limit that's not the typical "the rest of your life" situation. With magic or cused objects that force someone to tf it has to have a way to undo the magic curse or a time limit until the tf is finished. The only exception is stuff like a gameshow or a bet that causes a tf, or if the tf causes mental changes that effect the character. When I comes to mental changes I feel like it should still keep the character and not change them completely. A great example of this is if a character's favorite food is burgers then after the mental change it should still be burgers (or something similar depending on the tf).
What do you think? Do you agree, or have a different look on this situation?

(I also hope this makes sense and if have any questions for me you can)