Favorite part - probably traps or triceps. They're the only parts that seem to respond to exercise lol.
Least favorite - stubborn gut fat.
1) eat real food - more vegetables, moderate meat, moderate fruits, less grains, less sugar, less vegetable oils.
2) exercise - moderate intensity cardio, sprinting, heavy lifting, dedicated stretching and mobility.
3) live - relax, de-stress, meditate.
Disclaimer: I'm not professionally qualified to make any formal recommendations. I've just done my homework and I'm my own guinea pig. All of my data, unless otherwise cited, comes from a sample size of n=1 (me).
Worst, my "ain't got no mo elastic left from having children" stomach. As for favorite, it's a toss up. Before I started this my worst looking body part hands down was my upper arms, they were seriously hideous. Now they are one of my best parts, but probably not quite so pretty as my million dollar smile (mom swears that's what the orthodontist charged for that straitening job).