This is where the disconnect is for me; mundane code can sometimes be nefarious, and I find the mental space I'm in when writing it is very different than reviewing, especially if my mind is elsewhere. The best analogy I can use is a self-driving car, where there's a chance at any point it could make an unpredictable and potentially fatal move. You as the driver cannot trust it but are not actively engaged in the act of driving and have a much higher likelihood of being complacent.

Code review is difficult to get right, especially if the goal is judging correctness. Maybe this is a personal failing, but I find being actively engaged to be a critical part of the process; the more time I spend with the code I'm maintaining (and usually on call for!) the better understanding I have. Tedium can sometimes be a great signal for an abstraction!