Hi,
That depends... (on waveforms and voltages etc.)
If you have a fast rising transition, you have lots of harmonics right into radio frequencies.
If you have traces nearby that's sensitive, you have to be more carefull .
But you shouldn't ever use right angle corners if it is possible to avoid them (which it allways is), since they're more prone to lifting and to "decomposing".
Right angled PCB traces are the mark of poor amateur designers - why do you want to do it that way?