I think one difference between jumping spiders and a lot of other insects is that they very apparently "see" more readily and react as well. So they tend to appear to hold more personality in a way we can more readily interpret. They've also got that "huge eyes" thing going on that helps improve their cute factor*.
*Interestingly for humans most "cute" things tend to equate toward more childlike physical properties. Big heads compared to body size; large eyes; etc... That's why you see many "designer cute" dogs which essentially look like oversized puppies