I think you've shown, through Filly, that the move-towards-comfort vs avoid-discomfort formula is too simplified.
Among other things, the whole concept of discomfort/pain varies. (Some of us actually enjoy the "burn" of the workout!)
Discomfort/pain can = physical pain, from a pulling rein to a beating
Discomfort/Pain can = wakeup call, like a sudden slap
Discomfort/pain can = hunger, loneliness, physical ailment
Discomfort can come from loss of dominance, too
Some of these I, or my horse, try to avoid; some might make my horse (one of them, the dominant mare) fight back. The quick, sharp slap of a crop, though, usually invokes simply: "Huh?"