I have lost 3-4 workout notes because I accidentally hit the back button (mobile) or the ESC key (web). The workout has closed, discarding what I've written without giving me a warning. I've started writing my workout notes in the Notes app on my phone / notepad on my computer and copying them into Training Peaks so I don't lose them accidentally.

Suggested fix: add a "you have unsaved changes" warning so I don't accidentally lose my workout notes.