Why is a goal a good thing?

Elo

It seems to be an important concept that setting goals is something that should be done. Why?

Advocates of goal-setting (and the sheer number of them) would imply that there is a reason for the concept.

I have to emphasis that I don't want answers that suggest - "Don't set goals", as is occasionally written. I specifically want answers that explain why goals are good. see http://zenhabits.net/no-goal/ for more ideas on not having goals.

I have to emphasise again that I don't mean to discredit goals or suggest that the Dilbert's Scott Adams "make systems not goals" suggestion is better or should be followed more than, "set goals". see http://blog.dilbert.com/post/102964992706/goals-vs-systems . I specifically want to ask - why should we set goals? (because the answer is not intuitive or clear to me)

Here in ROT13 is a theory; please make a suggestion first before translating:

Cer-qrpvqrq tbnyf npg nf n thvqryvar sbe shgher qrpvfvbaf; Tbnyf nffvfg jvgu frys pbageby orpnhfr lbh pna znxr cer-cynaarq whqtrzragf (V.r. V nz ba n qvrg naq pna'g rng fhtne - jura cerfragrq jvgu na rngvat-qrpvfvba). Jura lbh trg gb n guvaxvat fcnpr bs qrpvfvbaf gung ner ybat-grez be ybat-ernpuvat, gb unir cerivbhfyl pubfra tbnyf (nffhzvat lbh qvq gung jryy; jvgu pbeerpg tbny-vagreebtngvba grpuavdhrf); jvyy yrnq lbh gb znxr n orggre qrpvfvba guna bgurejvfr hacynaarq pubvprf.

Gb or rssrpgvir - tbnyf fubhyq or zber guna whfg na vagragvba. "V jnag gb or n zvyyvbanver", ohg vapyhqr n fgengrtl gb cebterff gbjneqf npuvrivat gung tbny. (fgevpgyl fcrnxvat bhe ybpny YrffJebat zrrghc'f tbny zbqry vf 3 gvrerq; "gur qernz". "gur arkg gnetrg". "guvf jrrx'f npgvba" Jurer rnpu bar yrnqf gb gur arkg bar. r.t. "tb gb fcnpr", "trg zl qrterr va nrebfcnpr ratvarrevat", "fcraq na ubhe n avtug fghqlvat sbe zl qrterr")

Qvfnqinagntr bs n tbnyf vf vg pna yvzvg lbhe bccbeghavgl gb nafjre fvghngvbaf jvgu abiry nafjref. (Gb pbagvahr gur fnzr rknzcyr nf nobir - Jura cerfragrq jvgu na rngvat pubvpr lbh znl abg pbafvqre gur pubvpr gb "abg rng nalguvat" vs lbh gubhtug uneq rabhtu nobhg vg; ohg ng yrnfg lbh zvtug pubbfr gur fyvtugyl urnyguvre bcgvba orgjrra ninvynoyr sbbqf).

I suspect that the word "goals" will need a good taboo, feel free to do so if you think that is needed in your explanation.

It seems to be an important concept that setting goals is something that should be done. Why?

Advocates of goal-setting (and the sheer number of them) would imply that there is a reason for the concept.

Here in ROT13 is a theory; please make a suggestion first before translating:

I suspect that the word "goals" will need a good taboo, feel free to do so if you think that is needed in your explanation.

Like anything, it's a cost-benefit. Here's my impressions.

Benefits:

It feels good to accomplish the goal. (If I make a goal to run every day for a month and I accomplish it, it'd feel good. If I had otherwise happened to run every day for a month, I wouldn't experience that feeling of accomplishment at the end of it (in the same way).
It motivates people. What I describe above is part of "the carrot", but having goals also acts as "a stick". Because when you know you have a goal to do something, you're motivated to avoid the unpleasantness of not having achieved your goal.
Accomplishing goals boosts peoples confidence. When you are successful, you think, "I accomplished a Thing". This sort of explicit realization might not happen if you hadn't made it an explicit goal. With the realization might come feelings of, "I'm the sort of person who could accomplish things in general" or "I'm the kind of person who could accomplish similar things to the thing I just accomplished".
As a form of precommitment, it may help prevent you from rationalizing. Without a goal, it may be easy to say, "eh, maybe I shouldn't do this". But this is often a rationalization, short-sighted, fear-driven, impulse-driven etc. By setting a goal and sticking to it, you're sort of saying, "Hey future self - I declare that you don't have the authority to come up with rationalizations. You're not allowed to decide not to do this.".
(Each of these could be broken down further. Ex. you could make the distinction between feeling good right after accomplishing the goal of running every day for a month, and the feeling of looking back on that accomplishment 5 years in the future.)

Costs:

It's not "flexible". What if you set a goal for yourself, but subsequently realize that the goal isn't "what's best for you"? Like what if you realize that you've been seeking lost purposes or something? (There's a trade-off with the fourth bullet point of Benefits though)
It may be stressful. Having a list in your head of "stuff to do" is often stressful. Alternatively, you could just throw out that to-do list and say, "I'm just going to decide on the fly what's best for me to do; there's nothing that I have to do".
It also may be stressful in the sense that you are worried that you won't achieve it.
If you fail at your goal...
- It may make you unhappy (because failing is unpleasant).
- You may lose confidence and think, "I'm the sort of person that fails".
- You'll probably feel less motivated to pursue goals in the future.

Personally, I really don't like the fact that goals "remove flexibility". The way I see it, what I should do depends on expected utility calculations, and these calculations change as I acquire new information and make progress in my analyses. I don't like the idea of putting myself in a situation where I'm not allowed to pursue the option that I calculate has the highest expected utility.

But I do find them moderately fun and motivating, and so I set "flexible goals" for myself.

I should also mention that one of the most important things that happened in my life involved setting an absolute goal. In 8th grade I made it a goal to make the high school basketball team the next year. I was pretty bad at the time and conventional wisdom said I had absolutely no shot. But I was extremely committed and I did it, and this made me happy and gave me a lot of confidence (sort of; it's more complicated).

Re: generally applicable advice - I've never been a fan of it (in this context, and also more generally). In the context of goals, I sense that people are different enough such that it's pretty hard to find generally applicable advice. Ie. they weigh the costs and benefits in the bullet points differently.

I'm not sure to what extent this is true though. I'm not particularly familiar with the literature, and I haven't thought about it too hard. I just sense that advice is a lot less generally applicable than "people" make it out to be.