Stubborn - As easily as ISTPs go with the flow, they can also ignore it entirely, and usually move in another direction with little apology or sensitivity. If someone tries to change ISTPs' habits, lifestyle or ideas through criticism, they can become quite blunt in their irritation.
Insensitive - ISTPs use logic, and even when they try to meet others halfway with empathy and emotional sensitivity, it rarely seems to quite come out right, if anything is even said at all.
Private and Reserved - ISTP personalities are notoriously difficult to get to know. They are true introverts, keeping their personal matters to themselves, and often just prefer silence to small talk.
Easily Bored - ISTPs enjoy novelty, which makes them excellent tinkerers, but much less reliable when it comes to focusing on things long-term. Once something is understood, ISTPs tend to simply move on to something new and more interesting.
Dislike Commitment - Long-term commitments are particularly onerous for ISTPs. They prefer to take things day-by-day, and the feeling of being locked into something for a long time is downright oppressive. This can be a particular challenge in ISTPs' romantic relationships.
Risky Behavior - This stubbornness, difficulty with others' emotions, focus on the moment, and easy boredom can lead to unnecessary and unhelpful boundary-pushing, just for fun. ISTPs have been known to escalate conflict and danger just to see where it goes, something that can have disastrous consequences for everyone around if they lose control of the situation.