Is lunging bad for a horse?

False! lunging is actually good especially to horses who arent ridable as it is a way to give them controlled exercise. pros basically about everything! gives them exercise, also helps warm them up so if you are riding next, you dont have to warm they up as much, creates trust and a bond, helps you learn your horse, gives you more experience... cons would really only be if you have a grumpy horse who likes to kick (like my TB gelding used to be) or if they are stubborn and your not firm enough so they just stand or something lol! (: i always lung my gelding before riding as he can be a butt and it helps me predict his temperment for that ride.