5)Their exercise time is spent in the same position as the rest of their day...On their ass
There is probably nothing worse for a humans than prolonged sitting. Most of us spend the vast majority of our day in a seated position. Our exercise program should do the opposite, you should be on your feet as much as possible. This is a problem that runs the gambit, too. I know some people who spin 4 days a week as their primary mode of exercise. I also know people who warm up for their workout for 5 minutes on a bike and then go sit on different benches for 10 minutes at a time with 15 second intervals of bench press or leg curls interspersed between their sitting time. I'm not saying the bench press is not a good exercise, I'm saying that when 95% of your time is spent sitting and 5% of your time is spent bench pressing, why would you call that sets of bench pressing and not sets of sitting. Get up and move around, explore the space.4)Focusing on quantity and not quality
This is a big one. When people think of exercise, they tend to think of quantity and not quality. This can mean a couple of things. This can mean they are using terrible form to get a high number of reps which is a stupid thing to do. If you need momentum to move a weight for a prescribed number of reps you need to decrease the weight so your muscles can do the job. This can also mean they are using a partial range of motion. If you can't move a weight through the entire range of motion, lower the weight and use the full range so you can recruit all of your muscle fibers. Finally, this can mean that they are just training too much. If you beat yourself up in the gym day in and day out and your technique suffers you are only asking for trouble. This scenario typically leads to injury which leads to prolonged breaks from exercise.3)Sticking to one activity
Most of the time, people pick one exercise modality and just stick with it and ignore the others. Endurance athletes stick to endurance exercise, meatheads stick to meathead exercises, people who do yoga just stick with yoga, pilates people only do pilates, and the aerobics crowd sticks with aerobic exercise. This typically leads to burn out as people get bored, and it also tend to lead to overuse injurie. Specializing in one form of exercise will typically build up some attributes of fitness while neglecting others. To become a better rounded person as well as a more fit and healthy person, it's important to improve all facets of your body. This includes getting some conditioning in to work your heart, some flexibility training to maintain range of motion, some strength training to maintain bone and muscle health, some yoga and meditation to give your brain a break, and some balance and core work to help maintain good movement. When I first meet with clients, we come up with a plan to address all of these things either directly in our workouts or over the course of the week in a combination of workouts with myself and other fitness professionals.2)Overdoing it
Oddly enough, most of the people I assess need to dial back the number of workouts they do in a week. Unless you are an athlete, most people only need to lift weights twice a week. I often get clients who come in already exercising 4-5 times a week with no real rhyme or reason behind what they are doing. We have been programmed to believe that with something like exercise, more is better. This is not really the case. Most people need to exercise less and move more in their everyday life. The most common lifestyle I find coming to me frustrated for lack of results is a lifestyle that is spent sitting behind a desk for 8 hours and that exercises for 5 or more hours a week. These people need to get up and move more throughout the day while exercising 2-3 hours a week. There is a lot that goes on with sitting for long periods of time from a genetic expression level that cannot be reversed with any amount of exercise. Moving more throughout your day and exercising 2x per week is more than enough for people to drastically improve their health and drop excess pounds.1)Not balancing your stress account
Most people don't realize the benefit of balancing stress. More importantly, if you don't balance stress you can negatively impact your health as well as your ability to lose weight. This is ironic to me because I've heard many people talk about a mythical stress mode their body enters when they don't eat every 3 hours. While that stress mode is a figment of people's imagination, beating yourself in to the ground 5 days a week with exercise and then getting drunk on the weekends leading to poor sleep will certainly put your body in to stress mode. When this happens, many things can go wrong. You will not properly digest your food so you will not absorb the nutrients you eat which will lead to increased appetite. Your sleep will become negatively impacted which will cause your blood sugars to run high. Your immunity will be negatively impacted because your body will always be in fight or flight mode and will become incapable of both resting and digesting. As a result, you will not adequately recover from your overexercising and will push yourself further push your self in to stress mode until you break.It's best to look at your exercise program like a bank account. On the one hand you have stress debits such as strength training, conditioning, boot camps, crossfit, and aerobics classes and on the other hand you have stress credits such as yoga, meditation, tai chi, foam rolling/stretching, recovery days, and solid sleep. If you don't balance all of your debits with credits you will be on the fast track to stress bankruptcy, and that is certainly not a good state to be in. One of the best ways to monitor this is with heart rate variability. Heart rate variability can tell you if you are overdoing it and need to dial it back, or if you are underdoing it and need to dial it up. Fortunately for the technically savvy, there are many apps for that. The best idiot proof apps are Bioforce HRV and Ithlete, but there are free apps you can tinker with that require a learning curve.