What do you focus on when purchasing a watch?

Design, because if I don't like the design none of the rest matters to me. 

At the end of the day, I have multiple watches, so I need more that don't appeal to me. 

Design, how the watch looks and feels to wear is #1 for me, all other elements are important too, but won't buy a watch I don't think its attractive because it has a great movement, etc.

I put "design" as my answer, but it encompasses things like: usefulness, appearance, and mostly but not restricted to functions/complications, or "gadgets", as I would describe.

But even then, I do appreciate if the functions are realistic or are useful to a certain context. Although a lunar phase calendar would be great to get some appearance, personally I don't have any use for it. But I do enjoy the compass and thermometer functions on my SGW-100, despite not needing to use them, because they can prove useful if I have to travel to somewhere far and I can have these tools on a pinch.

Another vote for design. All options you listed are important, but if the design is not my style, no need to look any further. 

Depends on the watch. 

It's almost 90% the dial. 

If I don't like the dial, no need to go any further.

I'm also a design guy.  

What that means to me is that I'm willing to pay more for a watch with interesting design with an "inferior" movement than watch that is generally though to be a "spec monster".  

In practice, that means that I'm cool with paying $500+ for an NH35 movement if the design is extraordinary.

The first thing I check is the movement. My rationale: no matter how pretty the look, it has to run well. Your feelings about a watch will change and alter over time. The feel of the crown. Manual wind. Quartz. Auto. 

How will you feel if it stopped working after 6 months? If servicing costs run high? The movement is my way of separating the poor runners. It's like dating, look for red flags. You'll be happier in the end. 

Looking for my materials brothers and sisters like: 

They've got to be out there.  Just look at how much hype watches get when they are released in carbon or ceramic. 

Design sells. It's true for watches and it's true for most of the other products and appliances that we buy. Material and finish quality are there just to ensure that once bought they will not end up too soon into the dump or second hand market.

Design. Got to catch my eye first.

E. Features and comfort.

That's a hard question tbh. 

Nobody will buy a watch, if they dislike it's design. Right?

But i also won't buy a watch, if the movement doesn't fit the watch.

e.g. pricey watch and cheapo movement (Sinn)

Design first. If I don’t like the look, I don’t care about the rest no matter how good of a value it might be. I only have a few watches so they have to speak to me. No one outside the watch community knows any specs. They know designs and brands. I don’t care too much about appeasing people with big brands but I do like having iconic pieces. 

This is an interesting question.

For me, it is the design, but it is more complicated than that.

To me the design belongs to everything in a watch: the movement, the finishing...It first depends for what purpose you get your watch.

And before anything else, it starts somewhere: the case shape, which is a pure design thing.

I go for Sinn because I'm into the look and find the movements (ETA) to be good enough for me.  I actually perceive off the shelf Swiss movements like ETA or Sellita to be advantages because they will be easy and cheap to service in the long run.