In the big world of fast food where people want food hot, fast and friendly service all rolled into one there can be several problems. First of all might be that they hire young or younger employees. This can create several problems. A lot of younger people are doing these kinds of jobs just for money and do not really care about the job itself. They work their hours and do what they need to just to get by. No care in the world about the actual job itself. A lot of them don't take pride in their work even if it is fast food. They should greet each and every customer as if they were at their own house eating a meal together. Put on a smile, and do everything for the customer that they would want done for them.
One of the biggest reasons that they don't do more as younger people is because the pay is not so great. A lot of fast food restraunts do not offer benefits to their employees and so that can mean lower wages and crabbier people which in turn can cause poor customer service. If they offered more incentives to their employees then they might have happier, and more moviated workers. A lot of fast food restraunts are still offering the very greesy, high fat foods. Which if you come to a fast food restraunt isn't that the point? To eat the fattening foods? More and more people are finding themselves ordering healthy salads, fruit and low calorie beverages then ever before. More and more fast food restraunts are offering the healthier options but there are some that haven't joined in on the healthier option yet and therefore do not get as much of the customer base that others that offer them get.
The lack of high pay, and just the plain old fact that there are not as many people out there in this world willing to do the job of flipping burgers as there once thought to be is one cause of fast food service problems. The lack of people willing to do these kinds of jobs could therefore be causing service problems because those that are working there already may be forced into working more hours due to the fact that there aren't as many willing to do the jobs. This again can cause more problems in service because not enough people to clean the restraunt and bathroom, make the food and tend to the customers like they need to have.
To sum all this up I think I would say that lack of pay, lack of people to do these kinds of jobs and not offering the healthy or healthier options that more and more people are wanting may result in quite a few fast food service problems.