Lack of code reuse. (other than copy and paste) So they probably do the same thing over and over in different parts of the application. Reusing code is not tri

Lack of code reuse. (other than copy and paste) So they probably do the same thing over and over in different parts of the application. Reusing code is not trivial, the design has to be good, the code needs to be easy to find and call. It becomes harder as the number of people increases.