Are customers who want to buy leaving your website without ordering? If it is too difficult or too much trouble to complete a transaction they certainly will. Take a look at this humorous video from Google Analytics showing what online checkout would be like in real life.
I always tell clients that you must make it easier for people to do something than not do something. Spending time on getting interaction right is worth it. For years, a large part of our business was developing training programs for custom software applications used internally by businesses. Many corporate IT departments did not have usability or interface design expertise on internal development projects. It could take hours of training to teach people how to accomplish a task that would have been unnecessary if the interaction was more intuitive in the first place. Companies can require their employees to use something regardless of how difficult it is, but visitors to your public website have lots of options. Make sure that it is really easy for people to respond to your call to action!