Once I was working on a project using the Processing language (Java-based). I rememeber when I used some variable and then after that ++ inside in array (for example array[x++]). I remember I got screwed over big time and I spent quite some time figuring out why something was going wrong (I can't quite remember as this was a couple of years back) but then I realised that x++ was being incremented AFTER the array was indexed the original value of x.
Rust favours security over convenience. Rust does not want you to make silly little mistakes than can waste so much of your time debugging, which in the end makes it more convenient.