When was the last time you had a coffee? I don't mean in the office, but in a regular take out joint, one of those ones with a drive through window? Have you gotten to the window after repeating your order to the "big talking head" only to have it wrong when you get there?
When someone says ... "Can I take your order..." they should be prepared to do just that. Other distractions and conversations should not take them away from the service they are meant to be providing to you! Your team needs to learn the importance of this lesson - the Customer comes first and its always the customer that's infront of you that you should be looking after. Problems with previous customers or planning for future interactions should not impact the service you are providing at that moment in time. Now some of the blame should definitely be placed at the feet of employers here.
Your training should always include a Customer Service component and even for staff that might not necessarily be working on the front lines this module is a useful skill ... if for no other reason than they are better able to empathize and prioritze their work to better assist your front line team that is dealing with customers.
Remember - the goal at all times is not just solving the problem ... even Customer Service teams are involved in Sales and the best and easiest sale is one that your existing customers make for you! This happens through referalls and the only way you will get those is through Exceptional Customer Service. If your customers know that you will go the extra mile for them and that you are going to be there for them, they will be happy to recommend your company and its product/services to others. Conversly they will also be the loudest voice denouncing your service if it is not up to the standard that they expect and are paying for!!