You ashamed of your original face? The one you were born with then?
To opine myself on this one (because it's one I juggled with in earlier years), it depends on where the motivation and impulse comes from? People can have self-destructive and harmful self-images that drive them to change or attempt to change their appearance as a way of getting validation from others that is...incomplete or distorted if they don't have a self-confident or strong enough self-image to avoid harmful obsession over that fact (people obsessively dieting to the point of anorexia, or the people in tabloids who've gone to plastic surgeons a dozen-plus times because the nose just isn't right yet, and that kind of thing), and in those avenues those changes aren't originating from a place of good so they're not very good themselves?
In contrast, someone going into a diet/exercise-regimen with a goal of getting more healthy and looking better (but in a less obsessive, self-destructive manner based on others perceptions but on self-image and self-worth) is doing a good--and I'd be of the opinion that makeup and beauty products, or even cosmetic surgery, can originate from the same place.
Which, to relate back to transhumanism, seems like it'd also be an applicable standard? One could go 'off the deep end' and start replacing everything of their bodies with 'superior' mechanical components based off of a harmful or unhealthy image of themselves and those components that only feeds on itself and is more compromising and dangerous to them. While insisting on 'no artificial parts' always strikes me as a bit too blanket, Luddite, and hypocritical in its insistence when we do all kinds of things to adjust for damaged or inoperative biology already (glasses as an obvious one that aren't the 'artificial limbs for vets' angle that seems to come up usually in this conversation). Is there much of a functional difference between non-integrated parts we use to 'enhance' ourselves or correct failing/failed biological parts? I'd say no. So long as people are either correcting something, or seeking a healthy self-image/ability for themselves in a non-obsessive manner, then it's not objectionable in my eyes.
So my fluffy-headed diatribe essentially amounts to 'Moderation and good vibes, man!'
To roundabout to the actual thread topic...Human failings are a good source of drama and physical description that are more readily envisioned or accepted than robot-eyes and titanium skullcaps or what-have-you. I think a lot of sci-fi defaults to 'standard human' appearance for people just because it's easier to describe/portray and serves to make the robo-eyes and titanium skullcaps and whatnot more distinctive and recognizable when/if they do show up (Terminator saving its evil robot-skeleton images for the climactic conclusion, when prior to such it was just the admittedly stiff-acting Arnold we occaisonally saw using his Terminator-vision(TM)). That said, part of
that (especially in movies) was probably driven by special effects which couldn't quite capture it without being 'rubber mask'-y or otherwise unworkable. We might be getting to the point where that changes in movies, and maybe that'll drive more works to put less 'human' appearances in more often? Dunnow...