I also enjoy cooking and think it’s a good way to spend my time, so while I have no idea to what extent, if any, my own reasons for this parallel Zvi’s, here’s some of my thoughts on this:

Physical work

I enjoy working with my hands. Cooking is one particular activity that falls into this category (I also do several more esoteric and less immediately useful things along these lines). I find such activities to be (a) relaxing; (b) not physically strenuous; (c) rewarding—cooking in particular has basically the perfect properties[1] to be a rewarding activity.

[1] That is: the initial skill threshold for getting into the activity, and seeing useful/encouraging results from it is quite low; it’s possible to make small, incremental improvements from any level of skill; the feedback cycle is quite rapid and feedback is unambiguous; the task as a whole is decomposable into many sub-skills which may be improved separately; it’s possible to advance your skills in a variety of directions, according to preference; you can work on your skills in it at your own pace and in your own way; the skill consists of a mixture of sub-skills that require experience and sub-skills that can be improved by reading, etc.; much of the skill is transmissible (making it rewarding and pleasurable to discuss it with others) while still requiring practice to execute and also to develop your own personal approach to it (which means that if someone else discovers how to do it, you still have learning/improvement to do—it’s not simply algorithmizable). If cooking were a designed video game, for instance, it would easily win awards for hitting all the right psychological buttons for long-term engagingness and rewardingness!

Cooking as an art and a craft

Few people are very good at cooking—and even fewer, at baking / dessert cooking (which is what I am best at). It is a challenging art, and so it is rewarding, for its own sake, to become better at it, for the same reasons that it’s rewarding to become better at painting, or origami, or any other creative endeavor.

Cooking is also a craft—which is to say that there are “objective”[2] standards by which it may be judged. This means that it is quite possible to become indisputably better at it.

Due to these two things—and the fact that the outputs of cooking (being delicious food) are intrinsically enjoyable to consume—cooking brings pleasure to oneself and to others, and being good at it affords a person social status. (When you invite friends to your place for a group activity, and serve them a perfectly baked, sublimely smooth and rich chocolate mousse cheesecake, they will be impressed.)

[2] More precisely: highly interpersonally consistent in subjective effect.

Cooking as expression of affection

Cooking (and, again, especially baking) requires the expenditure of effort (both to create the actual dish on that occasion, and to have learned the skills needed to do so). That makes it a costly and extremely hard-to-fake signal. If you make something that your friend / family member / significant other / etc. particularly enjoys, and make it the way they like, that is also a signal—that you pay attention to their preferences, that you know them well. And, as mentioned above, delicious food is intrinsically enjoyable to consume. This makes the well-cooked penne a la vodka, or tiramisu, or pavlova, or whatever, an excellent way to express affection, appreciation, etc.

Quality

This you may take as bragging if you like, but I state it as simple fact: the desserts I make are simply better than the overwhelming majority of what may be purchased in even specialty bakeries. (There are many reasons for this; part of it is due to my skill and many years of practice, but much of it is due to the realities of the food service industry—ingredient substitution, the need for preservation and transport, inevitable laxity in standards of freshness—and other cost-cutting measures, driven largely by competitition and rent prices—and many similar issues.)

That means that if I want to have a really good slice of sour cream cake, or pavlova, or even something so simple as a mint chocolate brownie, I can’t buy one that’s nearly as good as one I can make. It’s not a matter of preference; the product is simply not available at any price (short of paying extreme, exorbitant sums of money to hire a really good personal baker, or something to that effect).

A distinct but related point is that if I want something made just the way I like it, well, again I have no choice but to make it myself. And let me tell you—being able to eat exactly the things I like, cooked exactly the way I like them, all the time—that’s one heck of a boost to my life satisfaction.

I expect I'd like cooking a lot more if I got to do it much more socially; cooking with a group of people, for an even larger group of people, sounds like tons of fun to me. Cooking for myself is garbage.

Wow. I really appreciate the curious spirit of this comment.

There's a way to cook efficiently in batches that can lead to better nutritional profiles at rather low cost.

A pressure cooker is a totally overpowered tool in this regard — brown rice/quinoa mix takes around 2 minutes of setup (put rice in, rinse rice, turn on), around 20 minutes of cooking that doesn't need to be monitored, and around 3 minutes to wash the cooker and store extra rice/quinoa for reheating later.

Chicken breasts mixed with some vegetables takes similar amounts of time.

I probably spend around 45 minutes per week cooking in the purest sense of the term (and a couple minutes here and there to re-heat in microwave and wash plates, etc) and I eat most of my meals home cooked. It's almost an order of magnitude cheaper than eating out if you want similar quality nutritious stuff that wasn't cooked in junk oils and seasoned with garbage.

I used to hate cooking, but there's a few things of types of food/cooking mixes that are very convenient — pressure cooker in particular is amazing. Hard boiled eggs. Oatmeal and electric water kettle that shuts off automatically once it hits boiling... Kerrygold butter and extra virgin olive oil if you want more calories from fat. Mix in some pre-washed or canned vegetables and put that all in an online grocery delivery and you're eating well at low cost in time and money.

Edit: Also, I find waiting for delivery orders to arrive inconvenient too. As long as the fridge is stocked with batches of made food, I'm always 5 minutes away from eating something rather nice — or instantly if I don't mind eating it cold and am in a hurry.

Indeed you can! However, I find that this approach is not worth it except in one case, because washing a box grater is annoying, and cubing the butter works well enough.

(That one exception is when making pie dough by hand, i.e. without a food processor.)

(Also, I expect the “cleaning is annoying” calculus is different for people who own a dishwasher… although some box graters may not be dishwasher-safe—I am fairly sure mine is not, for instance.)