Past owner of 5 pure Toyotas and one Toyota/Lexus.
[TLCv6-1980, TCv6-1999, TLCv6-2002, TCv6-2006, TCH-2013, RX450H-2017.]
Mostly very good experiences.
In my opinion, the only potentially dangerous situation, occurred with the Toyota/Lexus RX450H.
The potential danger resulted from the non detection of a front seat passenger (my wife), and the potential for non deployment of the associated passenger air bag. Advised by dealership, we tested this by releasing front passenger's seat belt, while underway. Before we did, the air con did not show a passenger temperature, and the a/c fan did not run on the passenger side, and then the releasing of the passenger seat belt yielded zero audible warnings, nor warning lights. The service team indicated that the air bag may not have deployed during an accident, (we both recall from about 4 years ago).
Our vehicles including, the TLCv6-1980 (ignition), the TLCv6-2002 (fuel pump relay) and the RX450H (battery + confusing warnings), each failed to proceed once each. Our total "Toyota" ownership time was (7+14+12+15+4+5) or 53 years. That was one "fail to proceed", every 17.7 years.
I'm keen on learning more, and finding out how to overcome some problems, that may occur in the future.
Also interested in after market accessories and spare parts.