If you run them side by side, you will often find that Google Maps does not try as hard as Waze to save seconds. It prefers routes that are easier to learn, as you yourself like them, with fewer turns (and thus fewer interruptions). It caters to the 90% of people like you that don't obsess about seconds. Of course, it also has get traffic into account. Perhaps, in your case, the intersection isn't that busy, but traffic information is noisy.
I think there must be a factor like local data quality: I stopped following Google Maps as closely because it does things like an unprotected left turn on a major arterial road to save 100 feet going to the next light.
I remember trying to use Google Maps in San Francisco at rush hour. In terms of utility, efficiency, and practicality, it was indistinguishable from some bus-riding programmer's idea of a practical joke.
No, Google, I am not going to make a left turn here, because I have someplace I need to be by Wednesday.
Another problem with Waze, by the way, is that the algorithm is designed to route you away from a busy intersection or a congested street without regard to whether or not going out of your way will take more time than just slogging through the street/intersection. Waze also likes to do stupid things like insisting you make a left onto a six-lane divided highway without a light.
And their pathing is just bad: it insists on cutting through a gated community to get to my place, something that's physically impossible. And even worse, the entrances to that gated community and my townhouse complex are on different arterials. It also doesn't recognize the entrance to my townhouse complex as a valid entrance too (if you try to enter via the entrance, Waze will shriek at you to turn around, get back on the arterial, and find the gated community). I've also seen it straight-up get lost before when trying to go to one bar that's near my office.
Because of this, I long ago decided that whenever I request a Lyft, and I'm going either to or from home, I will call the driver and say "My name is Amy, I requested a ride. I'm calling to confirm that you are not using Waze.", and I will hang up and cancel if they say they're using Waze, if they don't speak enough English to understand the question (I live in a pretty diverse city, so this is common), or if they demand why I'm asking and then start angrily grilling me about every detail related to my destination.
And, yes, the third scenario is sadly common. I have never seen people get angry in real life like Waze partisans do except where actual religion is involved... imagine the worst kinds of vim/emacs warriors, Linux/Mac/Windows fanboys, PlayStation/Xbox/Nintendo/PC zealots, iPhone/Android partisans, etc., except in real life instead of on the Internet. It's actually why I started calling ahead: I used to just wait for the driver to get here, get in the car, and then as soon as they start the navigation and Waze comes up, I would calmly say "please don't use Waze, it can't get to where I'm going". The reaction was, more often than not, angry and aggressive. They treat "Waze can't get to where I'm going" as an attack on their lifestyle. After dealing with abusive drivers who will call me a liar to my face, screaming "that's the only thing I have!" at the top of their lungs, getting violent (I had one lady who punched her steering wheel while screaming the aforementioned), and sometimes getting straight-up kicking me out of the car (my response is always "Gladly!"), I've learned to call ahead and filter them out, as I have no desire to come within 10 feet of nasty, aggressive religious warriors. Oh, sure there have been plenty of Waze users who will let me navigate them manually (I can navigate from my office to my home in my sleep) or who will let me open Google Maps on my own phone and listen to the voice nav from there, but the number of angry fanboys and fangirls with no emotional maturity means that I'm not willing to risk it.
And it's because of the aggressive religious warriors who I'm afraid to share a vehicle with, and to a smaller degree because Waze's pathing sucks in general, I've started to call ahead to make sure they're not using Waze even when I'm not going to or from my house.
