Having been born and raised in the Metroplex, evidently it's expected that I would have always hated Houston. For most of my life, sports gave me no reason to dislike or like the city, though. I was just indifferent. The Oilers were in the AFC and never a threat to meet the Cowboys in the Super Bowl, and the Texans have been anything but threatening during their brief existence, too. Growing up in an American League town, I rarely heard about the Astros, and when I occasionally saw them on TV, I'd half-heartedly root for them since they were the only NL team in Texas. As I was growing up, there was only one period when a Dallas team and a Houston team were both quite good and competed with one another for supremacy. From 1984-88 the Rockets and Mavericks were both in the top 6 of the Western Conference every year, but even then they only met in the playoffs once (Dallas winning 3-1 in the first round of the 87-88 season). In the Mark Cuban era, the Rockets have been an afterthought, with the Mavericks season lasting longer every year since 1998 (Dallas winning the only playoff meeting this millenium).
As far as I can tell, nothing in sports drove a Dallas-Houston rivalry very much until the San Jose Earthquakes moved South and became Houston 1836 (later smartly changed to Dynamo). Most rivalries arise because of something that happens on the field. For whatever reason personalities clash and physicality escalates until someone gets hurt. Then someone on the other team is hurt out of retribution, and the Hatfield and McCoy saga unfolds from there. It seems to me that the FC Dallas-Houston Dynamo rivalry is different. I honestly had no idea that Houstonians (Houstonites? whatever) hated us so much until they came to Pizza Hut Park on May 13th, 2006 with traffic cones on their heads and malice in their hearts.
So, why did Dynamo fans hate FC Dallas so much from the outset? Is it because they have to drink Dallas' toilet water? Possibly, but on a level they have to realize that's just a fluke of geography or resources. Is it because we had been so indifferent to Houston up to that point? I guess that would rub me the wrong way after awhile, but I can't help that in my few visits to Houston my only impressions were terrible roads and the omnipresent faint smell of sulfur.
Yup, must be jealousy over their living in a lesser city. That's the only explanation to their calling Dallas "Southern Oklahoma." It's a taunt that doesn't make any sense on it's face, since the Red River has always been the border, and there's no socioeconomic similarity I've been made aware of between Oklahoma and the Metroplex. If they we're part of Oklahoma, then we are no longer a larger, better market in Texas than Houston, I guess.
Anyway, Dynamo fans have been mean enough in stadiums, blogs, twitter, etc. that I'm done with indifference. Their other sports teams may just be pitiable, but the Dynamo have proven themselves worthy of outright scorn. Stealing a good team from San Jose Earthquakes certainly helped, as did the resoundingly anti-football tactics of Dom Kinnear. Did you realize they are painting their new field considerably narrower than a normal pitch simply because they don't have the personnel to compete with the width and speed of many MLS sides on a proper pitch? That sums up the Dynamo tactics pretty well: pragmatic, but not at all attractive or fun. The drudgery of absorb pressure, launch counter-attack, rinse, repeat is just boring.
Above all the Dynamo are worthy of ire because of their fans. In my experience, Houston supporters are more likely to toss smoke bombs, yell obscenities, make JFK assassination jokes, throw objects at officials and opposing players, or light flares than they are to show an appreciation for the beautiful game. Don't get me wrong, there's absolutely a place in soccer for heated rivalry, but Dynamo fans have regularly gone too far towards hostility, and it's unacceptable. We need to be loud and emphatic in our opposition, but with a basic level of respect despite the lack of that aspect from their end.
And when you get so annoyed with their antics that you want to be disrespectful back, just chuckle to yourself that every time you flush a toilet in the Metroplex you're providing drinking water to Dynamo fans.