My wife and I moved here (to Katy, specifically) 7 months ago from Minneapolis for my work. We were excited to try living in a new city and gamely gave it a go.
However, we have had it with this place and need to get out. As a service to others considering Houston, I will offer my reasons here. I am not trying to be overly harsh or insulting; this is my opinion having lived here for less than a year.
1. COST OF LIVING.
Living here is not as cheap as people say. For example, while it is true that housing in SOME areas is "cheaper" (meaning lower listing price) than many parts of the country (such as Minneapolis), those areas are usually very far out in the suburbs, or in extremely undesireable inner city areas. The "nice" areas in Houston are as expensive or more expensive than many other cities in the US.
On top of that, property taxes, homeowners insurance, and car insurance are all about double what they were in Minneapolis, and sales taxes are higher as well. Yes, there is no state income tax, these other items more than make up the difference.
Because of having to drive a lot, we spend 3 or 4 times as much on gas as we did before. The regular freeways are really bad here traffic-wise, but if you take the tollways you are paying even more. We spend about $300-$500 a month on gas and tolls, versus less than $80 a month on gas and no tolls in MN. (More on traffic later).
So, all in all the cost of living is much higher than you might think from looking at the price of houses out in the way-out suburbs like Katy or the Woodlands.
2. TRAFFIC/ROADS
If you move to the Houston area, be prepared to spend a lot of time in your car to do ANYTHING, not just going to work. Pedestrians and bicyclists are a rare sight, probably because the weather and air quality preclude being outside very much anyway (more on the weather later).
The streets of Houston will do major damage to your car. I thought Minneapolis had potholes, but it seems nearly every block in Houston has at least one giant pothole, as well us numerous cracks, bumps, etc, that make it feel like you are driving on an off-road course.
The freeways during rush hour are parking lots. I have learned to leave for work by 6:15am to avoid the worst of it, but if for some reason I leave too late it takes me double or more of my usual commute time.
Houston drivers don't seem better or worse than elsewhere. I don't see as much aggressive driving as I've seen elsewhere, but I do see a total lack of turn signal usage, which is annoying (though not enough of a reason to move away by itself

) The number of F150/Dodge Ram/other giant pickup trucks driven by one person as a commuter vehicle is astounding. What will they do when gas is $8/gallon?
3. WEATHER AND AIR QUALITY
Houston is hot and humid - no surprise there. At least the winters are mild, right? I wouldn't know, because it is still basically summer as far as I can tell (81 and humid right now, the day before Thanksgiving). In the middle of summer, even at 5 am on many days it was 80 and humid. When it wasn't super-hot it was raining.
The humidity and lack of real cold make for a very rich environment for mold, bacteria, etc. On humid days (which is most of the time) there is often a bad smell in the air; it smells like armpits, like dog poop, like mold, etc., depending on where you are. Natives have probably tuned this out, but I am bombarded with it constantly. Not only that, but my wife and I are having health issues (skin and respiratory) that we've never had before living here. My wife's allergist (a native Houstonian) told her that that is just what Houston is like.
4. HOUSTON CULTURE and COMMUNITY, etc.
Native Texans are very friendly and outgoing. I do like that about Houston.
The symphony, museums, restaurants, etc. in Houston are nice, though as I said before be prepared to drive a lot to go to them. We have given up on doing anything during the week other than watch movies at home because of the traffic.
Generally, people here don't seem to care about much outside their own circle of existence. At the grocery store, for example, most people just leave their shopping cart in the parking spot where they parked after they are done with it. So the parking lot is full of abandoned carts blocking access for other people trying to park. Another example: the streets of Houston are full of trash. Everywhere you look there are discarded fast food cups, cigarette butts, and misc. garbage and debris. Natives probably just overlook it, but if you actually look outside you see it everywhere.
The urban design of Houston is atrocious. Outside of a few nice areas, it is one of the ugliest cities I have ever seen. It seems like every block has a strip mall with an adult bookstore, a nail shop, and an abandoned storefront. Then the next block is an empty lot filled with weeds. It goes on and on.
There are a few nice parks in Houston but because of the weather they aren't particularly useful. I have always meant to check out Memorial Park but again, traffic turns it into a major excursion when all I want to do is have a relaxing time at the park.
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I could write more, but those are the main reasons for wanting to leave. If anyone has any questions feel free to ask.