And if an ISFJ is in a situation where they're constantly getting the short end of the stick, the stress will get too much. Traditionally, they are the type most able to put nose-to-grindstone, head in the trenches, and plow on without complaint through thick and thin, snow and rain.
It doesn't mean they're able to maintain that, though, depending on the circumstances. Eventually they WILL wear down. Also, sometimes anger at others is deflected into anger at self. It's still selfishness, because it's refusing to allow themselves to be a human being and it's refusing to forgive the other people involved (if you deflect the anger, you don't have to give it up, and internal anger gives people a sense of control and entitlement).
On the surface, I can see why y'all might think these things about ISFJs, but there's a lot going on inside. Worse, the ISFJ often is so focused on the external world and getting their responsibilities taken care of that they remain self-unaware. Their whole world is based on denial of their own human frailty, because their commitments are so absolute; they have serious trouble allowing themselves flex room.
Note that each type has a range of behaviors associated with it. Some ISFJs will be pretty well-adjusted, sweet, and non-domineering; others will be very pragmatic, practical, and unyielding. Still, Fe goes a long way towards presenting a positive self-image. (This is drawn from a life experience full of various ISFJ women.)