With all the moving you will do you will feel the water sloshing around and it is very uncomfortable. Drink water, but don't gulp down a few bottles worth.Even on the exercises where Shaun sets a number of reps to do, if you feel you cannot complete them safely, then stop! There is no shame in taking a break. With all of the jumping, twisting, and lunging in Insanity it is easy to hurt something if you have incorrect form. You will hear this from Shaun over and over focus on your form, not speed.The background extras can be annoying (looking at you Tonya.).While it would be great if the Beachbody team improved the stretches for now I would suggest doing some extra stretching on your own. A few weeks after beginning Insanity I noticed that my calves were noticeably tighter, especially while running they would be in pretty severe pain. Each workout does have a warm up stretch and a cool down stretch but I found that they weren't adequate.I considered myself in fairly good shape when starting Insanity yet I was still constantly sore. Working out for six days a week can be too much for some people.After a while I found the repetition very boring and it got to the point where I knew every line Shaun says by heart. They repeat the same videos every week, sometimes doing the same one twice in a week.You will sweat a lot and feel how hard you are working.You can workout from home, which for many people not only fits their schedules better but is also more comfortable.Relatively short videos (between 20 and 65 minutes, 45 on average).(I'll be honest, it makes me feel a little better when the extras seem to be in just as much pain as I am!) Pros of Insanity If you watched the video then you can get an idea how just how Insane this program is.