After exercising sometimes we are in a hurry or just a bit lazy and want to rush into the shower straight away.

No, no, you cannot be lazy when you exercise! And especially not afterwards. The cooling down and stretching is an important part of exercising.

By stretching and taking a few minutes to calm down your heart will go back to normal rate, your body will feel more flexible and you won't have any problems the next day.
Because everyone who exercises knows how it feels the next day after a hard workout.
And that pain will be less painful if you stretch and it is vital to avoid injuries.
Of course the warm up is just as important!

The cool down doesn't need to take long, 10minutes is OK.
Have fun exercising and remember to cool down.