I think it is unhealthy and a terrible idea to compromise the integrity of perfectly healthy teeth in order to attempt some impossible standard of beauty. For veneers, they have to grind down the top layer of enamel of your teeth, then they bond false-enamel inlays to the dentin. This is a ceramic substance which is not as tough as your teeth's real enamel and if the veneer is not absolutely, perfectly fitted, it can promote gum disease and you can end up with decay beneath the veneer. Veneered teeth can be more sensitive to heat and cold, and the veneers can be damaged if you have any bad habits like biting your nails or using your teeth to hold things or bite off threads or open hairpins.
Unless your teeth are actually damaged (chipped, decayed, or cracked) why damage perfectly functional teeth? If you are insecure about their straightness, braces are a much healthier alternative, and have other positive benefits, in that they can make your teeth easier to keep clean in the long run, which adds up not only to straighter teeth, but to whiter teeth, too.
You dentist can prescribe a course of whiteners, too, which can make straight but stained teeth look shinier.
I have not had veneers because I would not want unnecessary dental work done on my teeth. They are very valuable to me. I've never even had a cavity, so goodness knows I don't want to "fix" what ain't broke. I did have braces as a teenager, and I polish my teeth with baking soda once a month, and that's sufficient for me!