The occasional airport alerts are usually accurate, but even though it has enough information to accurately predict my commute

The limitation that I find particularly amusing (I get the notifications all the time, but largely ignore them) is that Google has flat-out failed to figure out that I am now a city-dweller. That is, it still always assumes that I am going to every appointment via car, despite the fact that 80% of my travel nowadays is by subway. So it is pretty reliably completely wrong about how long the trip is going to take...