Here is few out of 100s 1. Wrong category. 2. Submission in Top Level categories. 3. Site detail contain only keyword/not a complete sentence. 4. Submiting subdomains even after 95% directories clearly says don't do this. 5. Filling name like: dsadsf, sdaf, voalsdk, 6. emails like: ... ... 100. Editor not in mood
Each directory should have a page that states submission guidelines. If your site or your submission does not meet all of the criteria then it will be rejected. If you make errors in spelling, submit to the wrong category or submit junk sites then you could get rejected too. Hope this helps.
another important thing you left is design of the website I would reject any website of it has a bad design
This one is a big one. I can't count the number of submissions I reject everyday because of this. I mean one block of GA is plenty. Lately I've even been seeing other directories submitting that are full of nothing but GA'ds. Can't you just hear the sound of the swirling water?
Some directory owners will reject your submission for reasons, and let you wait for 6 months for the result, and even more of them will never give your message of indexing or not. They think they are another DMOZ.
Hmm... that really hurts... I don't think that's a good practice to delay the listing approval or rejection... It's better a website owner to be sure if his site was approved or not as shortly as possible. That's my policy.