They can't let it be, but they're wrong - we don't have the right to secede at any time. Texas does have special rights that other states don't have, but secession from the union ain't one of 'em. That's one of them "tall tales" you hear tell of.
One to be a little prouder of, perhaps, might be that flag etiquette allows us to fly our state flag at the same height as the Stars and Stripes when they're flying on separate flagpoles. Other states don't get that courtesy. A bow to our former independent-nation status, I believe. I don't know if Hawaii gets the same recognition.