Light blue jeans suit anyone who wants denim that looks like it's been worn in rather than straight off a shelf, and they're kind to most skin tones in a way dark indigo sometimes isn't. If you want one pair of jeans to do absolutely everything from smart to scruffy without a wash change, think twice, because the paler the wash, the more it shows its hand, grass stains, bike grease, the lot, and it won't go quietly into a work outfit the way black or dark denim will.
The easiest shades to live with sit somewhere between a soft powder blue and a slightly faded mid wash, nothing too icy or chalky, because those can read a bit stiff and new no matter how many times you wash them. A wash with a bit of unevenness to it, a bit of whiskering at the hip or fading at the knee, wears better and looks less like it's trying. Avoid anything with a stiff, cardboard feel straight out of the packet, that's a sign the denim hasn't had any softening done to it and probably won't soften much either, it'll just crack and go bobbly at the thighs. You want something that already has a bit of give when you pinch it, cotton with a small amount of stretch woven through feels better against the leg and moves with you instead of fighting you on the bus. On an ordinary day these pair best with things that have some weight or structure to balance the lightness of the wash, a plain white or cream top, a navy jumper, a tan or white trainer, anything too pale on top and the whole outfit can look washed out before you've left the house.
If you've got none in light blue and you're starting from nothing, go for a straight or slightly relaxed leg over anything too fitted, the softer wash already draws the eye, and a tighter cut on top of that can look more dated than classic within a season. A mid rise with a proper waistband that sits without gaping is worth more than a fancy wash, because a light colour shows every pull and crease where the fit is wrong, there's nowhere for it to hide. I've picked up a stiff pale pair thinking it would relax with wear and it stayed exactly as unforgiving as the day I bought it, so now I check the give with my hands before anything else.
Next time you're looking, feel the fabric first, if it doesn't move a little in your hands before you've even tried it on, it won't move much on you either.