More than 40% of people abandon a website that takes more than 3 seconds to load.
And the are never going back or recommend it to anyone. Google even lower your rankings if the website is slow and non-responsive for a while.
I realized how important website’s speed is more than 3 years ago. One of my websites lost search engine visibility (rankings) because it was too slow several days in a row. It was deadly slow, 10-15+ seconds on average page load.
The traffic decreased by more than 50%.