I'm going to go out on a limb and guess business administration and customer relations.
You really have to love what you do to do it well, and I think the cue maker exemplifies this ideal. I also think it is much easier to work in the shop doing what you love than it is to keep the books and records and answer the phone and hand hold the insecure or impatient customer.
The best ones have the chops in the shop and a gift for the administration. They are a rare breed though. Most would look at paperwork as a chore.
I'd like to procrastinate a little less. I've got cue's that are in different stages that were started over a year ago. Between work, yard/garden, and running a poker game two nights a week, I'll opt most times to take a nap instead of work on cues. If I ever get to the shop, I'm good for several hours. It's the gettting there that's a chore sometimes.
I'd say the process I dislike most is prepping the cue for finish. I also hate cleaning my spray gun after I spray the finish
Seal and finish. That is the single most time consuming part of cue making next to allowing the wood to age. Ive seen many different kinds of finishes. Some good some lousy. Sealing and preparation is really important and I think a step that is sometimes overlooked. UV is the probably the way to go from what Ive seen but who can affort it? Automotive clearcoat finish is nice but extremely dangerous to spray and still takes a ton of work to sand and polish out. Ive tried applying auto finish with a sponge brush but you still have a heck of a time leveling the finish and polishing it out. Tried lacquer finish with multiple coats but dry time is about 12 days to be able to sand and polish. Also tried using various types of finishes that you apply to the cue while its spinning in the lathe. Tons of work and a very average sheen. Tried epoxy and Superglue also but thats lots of coats and sanding and coating and sanding. I wish there was a simple effective way to seal and finish a cue that works good every time. Thats what most cuemakers need Lee. IMO