If you are so busy that you can't take the time to do that, then you are too busy. You need to slow yourself down - immediately. Because if you are not considering that, you are evading responsibility for your actions - no matter how small they may be. Everything you do has consequences which ripple out to affect tens, hundreds, even thousands of people. Your actions can hurt or heal you and others as well - often in ways rarely suspected.
Thoughts work the same way.
A mean-spirited thought is not seen by anyone else, but you know that it occurred. This is what conscience is. You know what happened. Pushing it aside is not a good idea. The next thing you know, we're all running around saying and doing an awful lot of things which are not good for the world we live in.