I don't need to buy a RAMBO SUPER SURVIVAL Ti EXTREME KNIFE. I just forge my own from ore, fire, and rocks when I am in a survival situation. I watched it on a movie one time I think (or the internet) so I don't need to practice in my mom's garden.
The knife that brings me the most joy is two....
I've talked of it before, but the first one is a cheap CRKT blister pack M16. My little girl saved her own money and picked it out herself as a gift for me. And it frankly does everything I need it to do.
The other is a old, well worn Cold Steel Recon tanto (back when that was a respected brand and knife). I am not sure it has truly saved my life, but it has been there for me during some difficult, or even perilous times. I have carried/used "better" since, but that knife has helped me through a few things.