Just read on Personality Page that ISFPs are likely to keep their true opinions to themselves, even to the point of mates not knowing them, and I'm thinking this is more of an ISFJ trait. It is Fe that seeks social harmony. Even the recent thread that Seymour posted about neurological connections to type said that ISFPs are more likely to defend their opinion or take action than an INFP.
This makes sense to me with the nature of Fi and Se. The PTypes description of Exuberant personality type, or ISFP, also clashes with the idea that ISFPs would always keep their opinions to themselves.
I agree that ISFPs could defer to their mates or stay in a bad relationship longer than they should (I am actually very guilty of WANTING to defer to my mate and staying in one bad relationship longer than I should have because of loving the person) but I don't think this Personality Page description is necessarily true.
There are so many fucking theories. One theory says this, another says that. It's absolutely silly.
I do keep my opinions to myself with acquaintances and strangers a lot IRL, though. I actually can be very quiet and passive unless provoked, and I've learned to keep my mouth shut to keep myself from bullshit. I was also very shy and afraid to stand up for myself until I was in high school. I was bullied several times in 4th through 7th grade.
I just don't think it's the nature of mature Fi and Se to never express themselves or fight back. I disagree.
If anything it is Fe which wants to keep the peace. I think some people have ISFPs and ISFJs mixed up. ISFJ is "the stereotypical submissive woman."