[johnfernandez]

Despite improving your application's performance, and avoiding unresponsive user interface, multithreading has the following disadvantages:

1. There is a runtime overhead associated with creating and destroying threads. When your application creates and destroys threads frequently, this overhead affects the overall application performance.
2. Having too many threads running at the same time decreases the performance of your entire system. This is because your system is attempting to give each thread a time slot to operate inside.
3. You should design your application well when you are going to use multithreading, or otherwise your application will be difficult to maintain and extend.
4. You should be careful when you implement a multithreading application, because threading bugs are difficult to debug and resolve.