Surprisingly not NSWF.
I have a theory about the beta quadra (and it also applies to the delta quadra, but don't tell them). I think that the dual-seeking and polr functions of betas are actually very similar (actually, you find this in that aspectonics stuff: both Ni and Fi are interior fields, both Se and Te are exterior objects, etc.)
IEIs don't like to be forced to pay attention to the "real world," in a Te way. Yet they think it's wonderful in an Se way.
SLEs don't like their emotions/interior state "seen through", or or for their feelings/interior state to be assumed in an Fi way. Yet they think it's wonderful in an Ni way. (the inspiration for this was this thread.
Because both the polr and the DS of betas are concerned with similar things, they can be externally similar (another reason for dual/conflictor confusion), but the nuances between the two are so different that the dual-seeking functions makes a normally-unpleasant experience, while still perhaps out-of-the-ordinary, wonderful instead of terrible.
I think this applies to the other two types, but I haven't figured out how yet. But there's probably a similarity between Fe and Ne and between Ti and Si too.
So, in conclusion, betas like things that are "painful" in one way but that "hurt so good" in another. The end. (Yeah, so that was a strained metaphor, but when I was thinking about this, that metaphor popped into my head, and I thought it was funny, so I stuck with it even after it was clear that it didn't really work.)