First, don't submit multiple times. When (and if) the editors ever get around to clearing the submission queue, they generally do so in the order the sites were received. Every time you resubmit, you simply drop your site down to the bottom of the queue.
Second, in the immortal words of Shrek, "Join the club. We've got jackets."
In other words, there are lots and lots and lots of website owners and webmasters in the same boat. DMOZ is staffed by unpaid editors, volunteers who basically will get around to reviewing sites when they feel like it. This is not their full time job by any means.
There are no guarantees when you submit that your site will be accepted, even if your submission is totally by the book and your site is the greatest thing since sliced bread. There are a lot of people who apparently get quite upset over the apparent unfairness of it all, but since a link from DMOZ is worth approximately the same as an individual link from an interior page on any other large, reasonably well-respected directory -- which is to say, not all that much, really, in the overall scheme of things -- IMHO it's not worth spending any time worrying over.
I personally haven't submitted a site to DMOZ in at least five years. But that's just me. I know there are some who wouldn't dream of launching a site without including DMOZ submission in the launch plan.
If it's something that matters to you, submit once and move on. If you get in, that's great. If you don't, it's not exactly the end of the world. There are loads of other more important things to spend your time and energy on.