Is your website …
If yes, most people will leave your site and rate your business as old.
Over 50% of searches on the web are on mobile devices. So if your site doesn’t work for mobiles, you’ve just lost 50% of your customers coming from the web.
Google places a large emphasis on loading speed for your search engine ranking. This means that if your site is slow, you won’t show up in the top searches for your business. Lost business.