Though being assertive makes your life comfortable to a great extent by guarding you against getting offended, and making people value your opinions sincerely, it has some limitations.
Let us see practically what assertiveness cannot do.
However, you will be subject to internal emotional conflict unless you exercise assertiveness in your life.
If you let people know of irrational stances that you have taken − like saying that you will quit your job if your salary is not hiked, when everybody knows that you need the job − chances are, people will start treating you without any serious thought.
On occasions where there is an immediate danger to life and limb, it's wise to let go of your rights temporarily.
Once you have taken a stance, try your best to stick to your resolution till the last. Remember that people will push you hard when you start taking a stance, and they will push harder once you give in, as the message you will be sending is that the next time you oppose something, they should try harder at intimidating you.
People are used to you behaving with them in a certain way. Once you start being assertive, the changes in your behavior could surprise, even startle others. It's always wise to start being assertive with one person at a time.