Jool. When I went in for my first ever flight there (and of now, only....), during the aerobraking, I had targeted slightly too low. I saved my poor laythe rover through making an emergency burn, but the whole time I was over it, I got a horrible feeling, like I was disrespecting something, and that I shouldn't be there. I breathed a huge sigh of relief when I got to laythe, but even then, I still am slightly nervous of it. Duna, on the other hand, feels, sort of like it welcomes you. I havn't gazed upon any other far off worlds yet, but I'm headed there.