Explain Load, Performance, Stress Testing with an example

Load Testing and Performance Testing are commonly said as positive testing where as Stress Testing is said to be as negative testing.

Say for example if there is an application which can handle 25 simultaneous user logins at a time. In load testing we will test the application for 25 users and check how application is working in this stage, in performance testing we will concentrate on the time taken to perform the operation. Where as in stress testing we will test with more users than 25 and the test will continue to any number and we will check where the application is cracking the Hardware resources.