Both. Could be you, could be any other ESTP who's acting SJ-like. I'm just trying to figure out what would lead to that appearance.
I thought it might be Ti, which like Si can be very particular about things, but Ti is even stronger in ISTPs. Maybe it's a combination of Ti along with a greater desire to express one's ideas led by Se? I really don't know, I guess I'm just trying to figure it out...
In addition an Fi-Ni loop can make then seem like an aloof INF.
ESFPs are pure sanguine, although ENFPs, who are "Sanguine-Phlegmatic," can often seem like ESFPs.
Keirsey probably called ISTPs "NT-like" for two reasons:
ISTPs share the same dominant function as INTPs, and in fact may resemble INTPs most when young.
ISTPs have teritary Ni, rather than inferior Ni. Combined with Ti, an ISTP may become aloof, resembling INT nerdishness.
However, ISTPs aren't like ENTs (ESTJs and ENFPs are, at least in terms of Te and Ne).
SPs aren't necessarily SJ-like unless somehow Si is amid their top 4 functions.
Thinkist: not optimist nor pessimist. I am primarily competent in the enneagram.
SX 9w1, SP 5w6, SP 3w4 | Split with the first two
Ti-Se-Si-Ni-Te-Fi-Ne-Fe. I'm always questioning this, particularly the Si.
Big 5/Global5/SLOAN: RCUEX