As a general rule, the more work the piece of meat did when the animal was alive, the tougher, but tastier, it will be.
Fillet steak is tender, but may not be that tasty.
Rump is often tastier, but can be chewier.
A well-done steak is likely to be chewier than a rare steak.
There are two lines of thought on cooking steaks - the most popular is to sear it on a very hot grill/pan to create flavour on the outside. The downside of that method is that the fibres in the steak will tighten, and so moisture will be squeezed out of the steak (as if squeezing a wet sponge).
If left to stand after cooking the fibres will loosen again, but with the juices gone it may be dry. One way over that is to deglaze the pan with a little water, or wine, adding some butter and pepper, followed by pouring over the steak.
Method B (less popular way) is to cook the steak gently on a medium heat with the aim of preserving the juices within the steak.
Having a pool of blood on the plate with a rare steak is disgusting, but is easily avoided by letting the steak stand on a rack covered with foil for the same length of time it took to cook. Personally I like pink, not bloody.
During cooking the juices in the steak will have been pushed to the outer surfaces by the squeeze effect (you can see this when flipping a steak over during cooking - juices [blood and fats] will flow to the surface. When left to stand excess blood will drain, and reabsorbtion will take place as the steak relaxes and the fibres loosen essentially, the juices in the steak are redistributed throughout the meat fibres.
The thinner the steak, the narrower the window for getting it just right.
If beef is to be eaten raw it needs to be very fresh which can be an issue with supermarket packed meats.
I always make sure pork is cooked through - personally, I don't like pink pork.
Chicken should never be pink; lamb is good pink, but I don't like it bloody.