I've had a long and exciting journey — full of failures and successes — since I first started working at Apple in 1983. I was part of the original Macintosh team and had two stints at the company (one from 1983 to 1987, and then from 1995 to 1997). Ask people who worked at Apple when Steve Jobs was around, and they'll very bluntly tell you it wasn't easy. There were days where he was impressed by my work, and there were days when I was certain he would fire me. But it was always exciting because we were on a mission to prevent totalitarianism. (You can read more about my adventures in my new book, "Wise Guy: Lessons from a Life.") I wouldn't trade working for him for any job I've ever had — and I don't know anyone in the Macintosh Division who would, either. My job as a software evangelist in the Macintosh Division defined my career. Here are the top 11 life-changing lessons that I learned at Apple:

1. Only excellence matters

Jobs elevated women to positions of power long before it was cool or socially responsible to do so. He didn't care about gender, sexual orientation, race, creed or color. He divided the world into two groups: "Insanely great people" and "crappy people." It was that simple.

2. Customers can't tell you what they need

In the early 1980s, Apple was selling Apple IIs. If you asked customers what they wanted, they would say a bigger, faster and cheaper Apple II. No one would have asked for a Mac.

3. Innovation happens on the next curve

Macintosh was the next curve in personal computing. It wasn't merely an improvement to the Apple II or MS‑DOS curve. Innovation isn't making a slightly better status quo. It's about jumping to the next curve.

4. Design counts

It may not count for everyone, but design counts for many people. Jobs was obsessed with great design. He drove us nuts with his attention to detail, but that is what made Apple successful.

5. Less is more

One of the key tenets of Jobs' obsession with design was the belief that less is more. He was the minimalist's minimalist. You can even see this in his slides: They had dark blue or black backgrounds with 90 to 190 point text and no more than a handful of words.

6. Big challenges beget big accomplishments

The goal of the Macintosh Division was preventing totalitarianism and worldwide domination by IBM. Merely shipping yet another computer was never the goal.

7. Changing your mind is a sign of intelligence

When Jobs announced the iPhone, it was a closed programming system to ensure that it was safe and reliable. A year later, he opened it up to third-party apps, and iPhone sales skyrocketed. This was a 180 degree reversal and a sign of intelligence and courage.

8. Engineers are artists

Jobs treated engineers like artists. They weren't cogs in a machine whose output was measured in lines of code. Macintosh was an artistic expression by engineers whose palette was software and hardware design.

9. Price and value are not the same thing

No one ever bought a Macintosh based on price. Its true value became evident only when you factored in the lower requirements for support and training. Jobs didn't fight on price, but he won on value.

10. But value isn't enough

Many products are valuable, but if your product isn't also unique or differentiated in some way, you have to compete on price. You can succeed this way — as Dell did, for example. But if you truly want to "dent the universe," your product needs to be both unique and valuable.

11. Some things need to be believed to be seen