New employees who want to completely change your processes when they haven't even done the process yet or see an entire process from start to finish. There's usually a reason we're doing it the way we are. I'm all for process improvements and efficiency, but at least have an understanding of the process first. And then make recommendations. I've been doing this process for a year now and cut it from a week long process to an hour. We think it's a pretty quick process - unless you don't know pivots/vlookups.
ETA - also not interested in the hours of meetings it'd take to make any more changes to our process, since it's a SOX control.
When a few of our new people started, they did that too. If you see room for improvement, by all means, speak up but not when you've been here a week and don't know how everything works yet. Totally annoying.