As an entrepreneur, it's very important to really believe in what you're doing. I started my first company in the US in 2000. It was called StubHub and was a secondary ticketing company. I believed that there was a huge opportunity to get rid of the touts on the street and create an orderly and secure market online.
While doing my research, someone put me in touch with Fred Rosen, then CEO of Ticketmaster. He told me: 'Eric, I have four words for you: it will never happen!' Just like that. It shook me, but I believed we had an idea that made sense. So we started the firm and eBay bought it in 2007 for £300m.
The irony is that after Fred left Ticketmaster, it went into secondary ticketing. If you're an entrepreneur, you don't want to think anyone is the Oracle of Delphi. You just have to be there and try.
Recruiting local advisers when I started Viagogo in London was another good decision. Many Americans think it's the United States of Europe, but you need to be respectful of every locality being different.
I've made my worst decisions usually when I've stayed on a path for too long because I'd become emotionally invested in it. With StubHub, we originally had two offshoots: StubHub was for consumers; LiquidSeats was the parent company that ran non- consumer systems - and that was where we wanted to go. But we should really have gone with StubHub earlier.
It wasn't until three years in that we got rid of LiquidSeats. I didn't make the decision to change quickly enough. You have to adapt quickly if something is not working, even if you don't want to admit that you're wrong. You have to give it a go, but don't take it personally if it doesn't work - just move quickly in the other direction. There's a fine line between being tenacious and being stubborn.
It's similar with managing people: it's never pleasant to fire someone, but if they're not the right person for the job, you need to move quickly. Deferring the decision is not good for you, for the employee or the organisation.