I will give a majority of you Astros fans credit because in my experience, most are diehards. Y'all live and die by the Astros maybe it's because it's the only franchise you can count on. The Oilers left, no hockey team, and the Rockets (while great in the 80's & 90's) are just your run of the mill franchise with a similar all-time winning % as the Mavericks (11th and 13th respectively). And let's be honest, it's basketball in the state of Texas. Football and Baseball are king (outside of San Antonio). So the diehards are the diehards for a reason.
When I lived there back in 2011-2014, I really enjoyed going to Minute Maid as you could find a ticket for $5 and sit anywhere you want. Plus it was baseball, and who doesn't like going to a baseball game. Although it cost more to park down there than it was for a ticket, beer, and a hotdog combined. And then my cousin moved down from St. Louis to work in the sales office of the Astros and I was able to get a lot of cool perks/seats. Hell, I was one of the few thousand there when y'all broke up Darvish's perfect game in the 9th. The rivalry started there for me personally because I was so mad that I couldn't frame that ticket as a keepsake.
But just like any successful run, you're gonna get new fans and when those fans start talking trash is what pisses most people off. Seriously, you're talking trash and you didn't go through the terrible years in the early 10's or get your heart broken by the White Sox. That part isn't you diehard's fault, as you're just the recipient of those types of fans/people right now. Oh, and trying to brush the cheating scandal under the rug.
All that being said, I am truly happy a DFW team finally has a close rival. We had some good battles with the Angels over the years and everyone likes to claim the Yankees as a "rival", but it's so hard to get up for those series as they're halfway across the country. Same with the Stars closest rival being 9 hours away in either Nashville, Denver, or St Louis and the Cowboys playing in the East albeit having good history with every one of those teams it sucks they're 15 hours away. The only other rivalry I would put on par with this one was the Spurs in the 00's and early 10's. But again, it's basketball in the State of Texas.
All that to say, F the Astros!
