I'll start at the beginning. The summer of 1997, where I watched Super Friends on Cartoon Network and the live action Flash series being re-run on Sci-Fi. He was a super hero, not Marvel and not Batman, and yet I thought he was pretty cool.
I went to a comic book store and got a newsletter. I still remember the heading on one article, "A Barry Interesting Time For The Flash." It talked about Mark Waid's two projects, Life Story of the Flash and JLA: Year One. I was fascinated by Life Story because I didn't think a major character like Flash could be killed off and replaced (the article told me about Barry Allen and Wally West, ex-Kid Flash, is the current Flash). Since Year One took place in the past, Barry Allen would also be in it, and it seemed accessible to a newbie like me.
So I read those while the reading the current Flash and JLA titles. Wally and Barry were two different characters, but I loved them both. Still do to this day. The Flash will always be one of my favorite comic book characters.
The transition between Flashes has been pretty good. Jay in the 40's and 50's, Barry in the 60's, 70's and early 80's, Wally in the late 80's, 90's, and 00's. It's like a baton that's passed. Unfortunately, that means no one knows what to do when adapting the Flash into TV shows, movies, or whatever.
Flash basically suffers from three things, 1) Identity Obscuration 2) The need to have a flashy personality which leads to 3) Creative License
As we see in STAS' "Speed Demons", Smallville's "Run", and The Batman's "A Mirror Darkly", the Flash's identity isn't established. It makes the viewer disconnect from the character. It's like his origins and motivations don't matter. And sure, they aren't the best around, but it makes the guy beneath the costume trivial.
All those Flashes had a strange personality. One that was definitely not Barry's, and can't even really count as Wally's. Yeah, Wally had that period after Barry's death where he was a hyperactive jerk, but that's far from the definitive Wally West. That's like if Captain America was a guest-star in a show and they put him in his Nomad break-away-from-the-US-government phase.
That leads us to creative license. By breaking ties with the comic identity and needing the Flash character to stand out as a guest star, these shows have gone in a direction with the character I'd rather they didn't. He's impulsive, he doesn't think first, and he's kind of rude. Almost annoying, even.
I just haven't seen the Barry Allen that brought me over to DC Comics. The level-headed one. The caring police scientist. The guy who thinks on his feet. His personality may not stand out as much as, say, Batman's, but he's the Flash, his legacy runs all over the DC Universe.
This isn't to say I've hated every portrayal of the Flash. Justice League eventually got Wally right by making him the team's conscience and showing him as the friendliest member. Two of my favorite episodes of anything are "Lightspeed" and "Flash and Substance". Both episodes show a wide range of the Flash's powers, personality, and world. Kid Flash may've been a little reckless, but he is still a kid and used his powers in an intelligent fashion. I've read New Frontier, and I think it's cool what they did to Barry. He's still testing out his powers, so he's got a bit more of a personality to him than the character some fans say was never interesting.
But anyway, that's my Flash rant. I think he's such a cool character, and even though he's not part of the Big Three, he's one of DC's major heroes. Following Flash's adventures is always a thrill for me, and although I don't like how his personality has been changed when he guest-stars on a TV show, I'm hoping some day there will be a definitive take on Flash's personality (even better than the live action show, which was so-so) in his own show or movie.