Yep, this is why people who are really good at this advise a breadth-first search that very quickly narrows in on the people who show real enthusiasm. Though it can be hard to accept when you're in the thick of fundraising, anything less than obvious enthusiasm is a no 99.9% of the time.
Think about it from the other side: if you were seriously considering making a company one of the few per year that you give millions of dollars, would you ignore their emails or cancel meetings at the last minute or sound bored on the phone? Investors get just as excited about a company they like as founders do about an interested investor or potential big customer.
Think about it from the other side: if you were seriously considering making a company one of the few per year that you give millions of dollars, would you ignore their emails or cancel meetings at the last minute or sound bored on the phone? Investors get just as excited about a company they like as founders do about an interested investor or potential big customer.