Startups or Big Companies: Which Is Better for Your Career?

I had a friend from NIT Jamshedpur. He was working in a reputed analytics firm in Gurugram. He was offered a fixed growth plan for next 5 years.

No doubt, he had a competitive pay of a corporate and perks of a startup. But he left the company in 15 months! Everyone wondered why?

Later on, I found that the company was not bad but he could not fit into that environment!