I wouldn't be too hard on yourself.
The girls who go to speed dating often to not have a set criteria of a guy they want.
I.e, the Mr. Right Bull Cra*, will most probably play heavily and they will be judging you on your ability to slot into a set of criteria, almost like ticking the boxes on a form.
Also the girls who go to these places, in my mind have a few issues too.
I once went to speed dating with a friend, I admit it, I didn't book it, he did and he needed some support so I went with him.
You could tell a good % of the women where heavy career chicks, the most attractive that I talked to (about 2%) of the room, all she talked about was her car, her job and how much money she earned, serious career chick, looking for a guy who earned more cash than her, strange in that environment the guys that had what she wanted, she didn't like them pysically.
Another girl I was talking to, she came pritty full on, about a 5 on the rating scale, but I could tell straight out she had issues, when I talked to another chick, she came over grabbed my hand and asked what I was doing, I'd only spoke to the chick for about 5 minutes and she acted like I was her husband. I just gave her a blank stare, almost akin to get the fu** away.
The rest of the girls huddled together like little hens, waiting for a guy to approach - hardly any of them where anything above a 5 in the full spectrum (healthy in the head and fuc*able), and it was plain to see most of them had a set of criteria points for a guy to fill, they had an agenda for the type they'd date.
No I didn't score on speed dating, the girls I was slightly interested in, where on reflection dull and boring.
Also I didn't wait for the sit down, I aquired numbers prior, without waiting for some report card bull0cra* - I received about 6 numbers with contacting 2, with no replies from either.
So I went out with my mates and pulled a more level headed chick, who didn't have a stupid criteria of needs requirement to get intimate, that revolved around some fantasy magazine tat.
Speed dating is hardly filled with normal level headed chicks anyway - I mean if she was desirable, why would she be there? It's almost like online dating but worse - It's like they fail at online dating so they try speed-dating -
Also speed dating is awash with loosers, I was surrounded by beta ti*'s hugging pints, whilst I dragged my friend from girl to girl - You'd think you'd clear up in speed dating, you'd be wrong - The girls usually have an agenda, unless you slotted in, you wont get there - That agenda seemed to be one that described MR Right, unrealistic expectations, hence why there where single.
Roissy doesn't like it also (found it though a google search)
http://roissy.wordpress.com/2008/05/29/speed-dating-sucks/
The guy is a self confessed playa, who talks like he knows the shi*.