I think for me the main reasons the electric is so addictive are the primal scream thing - both in that the guitar can roar LOUD thru them 4x12"'s which evokes some primal feelings and tingles the spine (I still get goosebumps sometimes when I wail a lead or listen to Angus Young loud) - and that the music it's used with allows the player also to scream when singing. Primal drumbeat trance-like hypnotism is a plus as well in band playing, and it's even very physical usually to play rock, easy to break a sweat.
And also, it's an instrument that rewards well and is very easy to play - you don't need to learn much anything to sound quite OK, at least enough to please yourself with it. Yet there is infinitely more to learn and explore, you never hit a ceiling on what more you could learn. And also you don't need a drop of musical knowledge or understand any theory to be able to play in bands etc. no problem. And deep down you also know that you _could_ play just as well as any guitar hero if you just put enough practice into it. Few instruments can be so easily mastered as guitar.
Add to those two the tinker factor, guitars are infinitely tweakable and can be personalized to no end, collected etc. and they are beautiful, functional objects to also look at and simply just owning them is pleasing.