Why Software Testing Is Important?

Sometimes it comes in mind that why software testing is equally important as of development. Before describing this first let us know what testing exactly is.
There are many definition of software testing but in easy words it can be understood as "an activity to check that whether the actual result matches the expected result to ensure that the software is free from bugs or defects".
Releasing software without testing can cause monetary and human loss, as history is full of such examples. 

Now let me give few examples which will clarify the question that why testing is important.

i) On April 26, 1994,  Airplus A-300 airlines crashed killing 264 people due to bugs in a software which caused malfunctioning and finally led to crash.
(ii) In 1985, therac-25 radiation machine malfunctioned due to software bug and delivered lethal radiation leaving 3 dead and 3 injured.
(iii) On April 1999 software bug led to failure of 1.2$ billion military satellite launch.
Apart from these examples there are many more in the history, even when Microsoft was launching it's operating system 98, it crashed on the day of launch because of bugs.

I hope now answer to the question "why software testing is important" is more clear as monetary and human loss is more precious than the commercials involved in software testing.

Thank You !!!!