When deliveries of the Tesla Model 3 began last week (29 July), Elon Musk said he and his company would be going through "production hell" for at least the next six months, as half a million orders are fulfilled.

But a day later Musk opened up on Twitter to reveal that this was more than just a throwaway soundbite to show how hard Tesla is working to deliver its cut-price electric car.

When asked if the ups and downs of his career make for a more enjoyable life, Musk replied: "The reality is great highs, terrible lows and unrelenting stress. Don't think people want to hear about the last two."

Naturally, given how social media demands our private lives to be ever more public, Musk was told that his fans would indeed like to hear about the stresses of running car maker Tesla, rocket manufacturer SpaceX, tunneling firm The Boring Company, and brain-computer interface startup Neuralink. Musk said: "I'm sure there are better answers than what I do, which is just take the pain and make sure you really care about what you're doing."

Musk opened up even more in a separate message, answering a tweet asking if he is bipolar with "Yeah", before elaborating: "Maybe not medically though. Dunno. Bad feelings correlate to bad events, so maybe real problem is getting carried away in what I sign up for."

Circling back to his comments at the Model 3 launch, Musk adds: "If you buy a ticket to hell, it isn't fair to blame hell..."

It is no secret that Musk leads an incredibly busy life. Not only does he run several companies at once, he is more involved with the hyperloop train project than originally planned, wants to colonise Mars by 2040, has begun selling a new form of solar roof tile, and plays a key role in Open AI, a non-profit aimed to regulating the use of artificial intelligence. He also has six children from two previous wives and is now dating the actress Amber Heard.

Although not mentioned for several years, Musk's side project involves transforming the Lotus Esprit submarine from the James Bond film The Spy Who Loved Me into a real submersible, powered by a Tesla electric motor.