#[] - why the [] if # already makes that line different from the usual code? seems superfluous
'a - is that thing next to 'a' a smudge on my display? Did I forget a quote? better wipe the display with my finger
'&a - "mut" and "ref" but ' ?
foo! - yelling out function calls. "print!" "exit!" "macro!". Angry Codes!
foo? - when you're done yelling, make sure to ask existential questions of the return result. This one I have the least problems with since it actually makes me question the return value ("hm, something's weird here, it could be null, pay attention"), but when coupled with the yelling, just makes the whole thing look dramatic. "do_it_now!(); did_we()?"
fn - by itself not a huge deal, but the list of truncated words that are used frequently is "impl", "mut" and "pub". I save some characters (am I really in such a rush?) at the cost of reading this broken English "f-n impl moot pahb". At least C doesn't have that. Pascal had "interface" "implementation", "begin", "end", etc. Java has "public", "interface", "extends", "class".
Default for Borrowed - suddenly English! No time to type 'function' or 'mutable' but "Default for Borrowed" is a-ok?
underscores all over the place in the standard library. Even C doesn't have that many, mostly in the _r variants that were added.
unwrap() - what does that word have to do with errors? (I know what it does) It wouldn't be my first choice.
I have a whole list of awesome stuff, meh-stuff and wtf-stuff I noted down about Rust while trying to learn it (on multiple occasions), and there are a lot of excellent things about Rust, but the aesthetics of the language are important, otherwise we'd all have no issues coding in Brainf*ck.
Yes it's possible to go nuts with syntax, but this just feels like the "programmer art" of language syntax. I think it's usable (clearly), it's just not elegant to me.