Is Houston really bad?

The last two days l've been talking to some of my parents friends about how I plan on moving to Houston to attend a trade school for automotive machining when I'm 18, and they told me Houston is terrible. I told them that out of any of the big city's in Texas Houston is reported to have the lowest cost of living and they replied "there's a reason". This is the first time I've heard it's not great. Another lady told me to stay on campus because of traffic etc (which I can't as it's not a college campus) but I figured it would be rough as it's a bigger city than I'm used too. My plan was to get a decent job and either rent or just buy a house depending on what would be cheaper in the long run. What are your guys thoughts, and is there anything I should be prepared for?