It sounds to me like your buying knives other people like/suggest. How do you buy knives? In store or order online? My advice- find a knife you actually like, doesn't matter if its a ~$100+ spyderco/benchmade/Emerson/whatever or a $10 Enlan. You bought those three based on suggestions you received here (or other places) right? What you need to do is go out and handle a bunch of knives all at once, at a B&M store or a knife/gun show, find one knife you actually love and carry it.
Another suggestion would be to add a small knife to your keys, I rotate a manbug or one of a few different ladybugs (recently it's been my ladybug salt hawkbill) and my wife rotates a ladybug or a kershaw Chive. That way you always have a knife but don't have to fill your pocket with something you don't care for.
One other suggestion, get a small, lightweight ~3" folder as slim as possible, a delica or dragonfly or a rat-2 or a kabar dozier, something that takes up no room clipped to your pocket, you'll find yourself carrying it more and the more you carry it the more you'll use it and begin to rely on it and rekindle your like for knives.