Bless, we have ~same story except I dropped out of the state school with a 2.8, and got into Google in 2016 due to what amounted to luck, I didn't even have other offers for the W2 McDonald's jobs. Life is a crapshoot and there wasn't a significant difference between my coworkers there and coworkers I've had everywhere else.
I'll take any excuse to talk about myself ;) Thank you for being curious -
I just absolutely do not buy that I took ~5 CS classes and did a great job on the interview questions.
I don't think I did a great job -- but, I was a deeply specialized self-taught iOS engineer who had built a point of sale.
When you're at Google, work is more episodic and less in-depth, so I had a seemingly unusually wide and in-depth knowledge base.
And iOS devs were considered hard to get. And Google had a special focus internally on getting iOS-specific interviewers who, at least in 2016, usually did a lot of work with non-iOS specialists.
So you have these sort of inherent biases towards me seeming relatively impressive to their day-to-day experience with other Googlers. Then, I'm fairly convinced the leetcode problems we do add a significant "luck" portion.
I spent about 6 hours a day, 6 weeks before interviews, in Cracking the Coding Interview and was still missing problems in the 1st chapter towards the end.
I'm selling myself short, probably. But looking back, I see it as luck, structural factors, and what pushed it over the top was focusing on communication / thinking out loud in the interviews. As long as you're intelligent, familiar with the material, and your interlocutor is having an okay day, you'll come off well.
