Assuming it is a show that appeals to me (based on trailers, recommendations, etc), my general rule of thumb is to give a series at least two episodes to win me over.
The logic is that the first episode is often compromised by the need for character introduction/development and often does not really reveal the true vibe and pace of the show.
IIRC, the first episode of Dexter left me thinking that I did not want to watch it. Seems like it put emphasis on how Dexter got off on killing and I did not really want to watch that sickness for entertainment. However, the second episode wasn't so bad, and by the third I was totally on-board!
In your case with JJ, since you watched season 1 and were non-plussed, I'd call it quits.
BTW, you didn't list DD. Did it make the grade? What about The Punisher?
IF was the one that was lukewarm with me. Danny's character was too unstable for me. In places he seemed to have a mature sense about what is right and what matters; in others, he was like a petty 12 year old living in an "all about me" funk!
I might not like JJ if it was a guy, but there is something about a hot chick with dark side and attitude that could beat the crap out of me!
Oops! Did I say that out loud?