I keep hearing the recommendation to make your SWR as low as possible and that would imply good tuning.

I'm a new HAM and made a centre-fed half wave fan, 40m, 20, 15m. It works, and pretty well.

I tuned it with a NanoVNA and the SWR is about 1:1 - 1:2 for all bands I use.


But I suspect there's more to tuning than just SWR.

 - Is the perfect antenna going to be (50+0j) Ω? 
 - Is it the imaginary part that changes the SWR?
 - How do you get a piece of copper wire to change its resistance to get to 50 Ω if its not?
 - How does all this fit together?
 - If I mess with it enough, am I ever going to get close to (50+0j) Ω?
 - Should I even care, if it works pretty well as is?