Well, there's notice and there's notice. Hands get the time invested because they do so much. Feet are usually left in slippers at the minimum, simply because the main function is to be stood and walked upon; for the most part time used in articulating the foot doesn't make a huge impact. But do a modern dancer performing barefoot. Vickie is almost agonizing to watch in that circumstance, simply because she has shovels from the ankles down. The foot bends and flexes as it pushes the body around, and gets extra flexion added from bodymass trying to do what mass does, and stay in motion. The mind doesn't consciously analyze signals that subtle, but it does pick them up, and if they are not 'right', the mind will pitch a fit. That is the biggest hurdle in CG...not breaking the illusion. For this subject, well, most of the footwear ladies wear of the sandal variety are slip-ons, and if you ever watch, a large percentage play with them constantly. If they're nervous or excited, but are trying to sit still....well, it has to come out somewhere. Like a hand gesture, it can be a nice little characterization item. Or it can be a time hog and utter waste of same.