Logos should be appropriate in its feeling. It is like a personality thing; it is a core idea and feeling of it. If it is for sports, it may be bold and dynamic, if it is in fashion it needs to be elegant
Distinctive & Memorables
It has to be unusual enough to persist in our mind. If you see it once or twice, you should be able to describe it to someone or doodle it in a piece of paper.
The logo should be able to be reproduced in every pixel size. Nowadays, logos are used in the email signature, Twitter and Facebook Avatar to the small as fav icons on the top of your website.
Finally, a bad logo is something Generic and too complicated
Who is Sagi Haviv?
Sagi Haviv is a Principal Designer and partner at Chermayeff & Geismar & Haviv. He has designed logos for world-renowned firms and sports championships. Graduated from The Cooper Union School of Art, he joined the firm in the year 2003 and he was added to the masthead of the firm.
Sagi Haviv is an expert on the effective logo design process and a constant contributor to PBS, Bloomberg Businessweek, Fast Company, and Meet The Press of NBC. He goes around the world to speak about logo design addressing in various conferences like TEDx, HOW design conference, Princeton University, Columbia Business School, the Onassis Foundation, the Brand-New Conference, the Americal Advertising Federation, and many others.
Sagi Haviv is also a faculty in School of Visual Arts in New York City, where he teaches Visual Identity Design.