An adjective for a person who "is looking for problems"
How would you describe a person who "is looking for problems" with one adjective?
Examples:
"A person who purposefully does something unnecessary for a particular reason (i.e. curiosity?), from which they won't get any joy or profit, but which might start an argument or cause problems/complications."
Elaboration:
Imagine the situation when you are in the underground parking lot, where places are grouped by 3 and each of this groups is partitioned with pillars. Now, there are 2 ways of parking your car. One is to park it at the place of the group, where all 3 places are free. This is a regular behavior. Another one is to park your car on the place next to another car, which is not parked right between the markings on the ground (taking up some space of your parking place), so if you park your car on the place next to it, it will probably partially obstruct driver's door opening., while you can enter/leave your car with ease. It is the only way to park your car at this particular place, you can't park it so that the driver of the adjacent car won't struggle to get into their car (they should be able to get in, but they will struggle a bit), you haven't done anything "against the law", you didn't really get any profit from it, but you might have caused a problem to another person (especially if they are not skinny), who is not keen on parking their vehicle correctly. How could you describe yourself in this situation with an adjective?
If it's deliberate - antagonistic (link)
1. acting in opposition; opposing, especially mutually. 2. hostile; unfriendly.
or troublesome (link)
- causing trouble, annoyance, or difficulty; vexatious
or more awkwardly - troublemaking
If it's careless/reckless, maybe boorish (link)
- of or like a boor; unmannered; crude; insensitive.
or loutish (link)
- like or characteristic of a lout; awkward; clumsy; boorish.
Edit: Leaving my original response as is, but to address the elaboration on the original question:
I think the question of motive is really important in this scenario. In your parking lot example, the person parking outside the lines has done something wrong. But I can see plenty of motivations for the person parking up close to their driver-side door, and each infers a range of different adjectives.
- They're doing it to deliberately inconvenience a wrongdoer, or demonstrate the wrongdoing to the perpetrator. (antagonistic, indignant, vindictive)
- They're doing it because the parking spot next to the wrongdoer is superior in some way to an empty group of spaces, and they refuse to modify their behaviour just because someone else has done the wrong thing. (unyielding, obstinate, stubborn, uncompromising, adamant)
- They're doing it in the hope that it will start a confrontation with the wrongdoer. (confrontational, pugnatious, belligerent, bellicose, combative, adversarial)
- They're doing it so they're not inconveniencing a third-party by parking outside their own lines. (righteous, virtuous, principled)
I think antagonistic is still probably the best general answer, but hopefully some consideration of the different motives might narrow it down to something more accurate.
Instigate [in-sti-geyt] /verb (used with object)
to cause by incitement; foment.
to urge, provoke, or incite to some action or course.
adjective form: instigative
Source: Dictionary.com
Or
Provocative [pruh-vok-uh-tiv] /adjective
- tending or serving to provoke; inciting, stimulating, irritating, or vexing.
Source: Dictionary.com
There are two expressions I'd use to describe exactly the kind of person described by the OP. One of them is dialect, and the other is vulgar.
In Scotland and N Ireland (maybe elsewhere too?), a person who enjoys inciting arguments and disputes, or is generally oppositional, is described as contrary. This is pronounced contrAIRy, with a strong stress on the 'a'.
More generally, a deliberate and gratuitous troublemaker can be called a shit-stirrer.