Wow, It's hard to believe that anyone would quit, but I guess there is a reason only a small portion of the world is certified to dive. I'm not sure what is that bugs you... maybe you are scared, maybe your instructor sucks, maybe your gear is ratty..... maybe it's cold.... but here is my point of view and some things to think about.
First about me: I just finished my open water certification today. I'm going on a cruise to the Caribbean next week and I have three 2 tank dives scheduled in Wed, Thur and Fri of next week in Roatan, Costa Maya, and Cozumel. I couldn't be more excited. I used to own a salt water fish tank and I have always wanted to swim in a reef. Scuba is the way to go. It will be the highlight of my trip. My instructor is good, but not ideal. I'm not going to bash because he did what he was supposed to. He tought me how to safely become a beginning diver. We dove yesterday at Mammoth Lake in Lake Jackson, TX. The dive shop there was friendly but the viz was only 6 feet. The water was 50 degrees and it's not exactly my idea of a good first dive. I still had fun and made it. Today we dove at 288 Lake in Houston, Texas and the viz was 20 feet and the water was 56. I hate being cold. I was worried I would get sick or freeze my ass off. I am still nervous for the first couple minutes when I go under. After I relax I'm fine.. .but it takes a minute. I'm still stoked about the Caribbean next week and I'm glad I finally got my certification.
As for you:
1. Why did you decide to dive? What was your dream? Did you taste the dream and want more? or decide it was nasty?
2. Did you have a bad equipment or location experience? I've eaten in some bad McDonald's, but I still love their Quarter Pounder with Cheese. Don't let one bad dive close you off to something you might enjoy.
3. Do you have an instructor who thinks he is Sergeant Hard-On from the Marine Corps? Take a deep breath and realize that under all that gruff and puff is someone who gives a darn and wants to make sure you will be okay on your own. Everyone learns differently and likewise everyone teaches differently. It's okay if you don't like the teacher, but make sure it's for the right reasons. It's good to have someone make sure you can do safety processes right. Your life is on the line and they probably won't be there when you NEED to do it.
4. Did you have a bad equipment experience? There is a wide range of equipment and doing scuba with the wrong equipment will be miserable. A good instructor will take the time to make sure you have the right gear and that it fits right. Speak up if something isn't working. Nobody wants you to have a bad time.
So give it some thought and let us know why you are thinking of quitting.