I need a loose schedule or a loose plan or else I won't get anything done, especially long-term. I am resistant to repetition, which is basically what a schedule is, because it is boring, but I recognize that it is necessary for making progress yet not burning out. When it comes to getting good at a skill, for example, you often have to practice it. I hate that, but it's just reality.
My natural work style is to do intense, perhaps prolonged bursts of working on something that leave me wiped out afterwards. I do much higher quality output this way. Schedules and consistency kill my creativity because I cannot summon it on a schedule. This leads to a lot of goofing off and half-hearted effort as I wait until I feel, er, inspired.
I am the kind of person who would prefer to ignore nearly everything for long periods (including stuff like sleeping and eating) while I work on something I am excited about or interested in, followed by a long period of recovery and not doing much of anything. This is not really spontaneous mentally as I am preferring to NOT be interrupted with a series of regular tasks. I will take breaks and spontaneously do thing unrelated to my focus, but it is not often pre-planned. Interrupting myself is fine then, but I don't like others interrupting me so much; I suspect this is common to introverts.
Anyhow, I have lived that way for a year here and there and it's very chaotic. I don't have any regular eating or sleeping schedule. I can lose touch with people and time. But I feel very energized. I don't find myself so discontent with the present.
My problem with planning ahead is not that I can't do it, but that I don't feel happy with it even if all goes as planned. I feel like I am checking off a list and not enjoying anything. If it doesn't go as planned, then I get irritated. Having loose structure or general ideas and then improvising as I go is not only more enjoyable, but I often am more satisfied with the results. Pulling something off is better to me than finishing a to-do list.
I am also a creature of habit, despite all that. Most of my habits are bad, but I recognize that schedules are good habits, ones which often anchor me to reality and force me to look after physical needs.
I can relate to not liking certain surprises or randomness or deviation from plans. People just showing up, constantly rescheduling or cancelling, and not thoroughly exploring an idea (feels dismissive or shallow) can annoy me. I prefer other people to be more consistent than me. It's like I can be spontaneous or less structured when people around me are more stable.