It all depends on what you truly think.....
But smoking cigarettes can cause lung diseases such as COPD, Emphysema and chronic bronchitis. You can also get lung cancer or if you have asthma you can have attacks, more attacks or worse ones. Could happen right away or take time, depending on the person and situation, how much you smoke, what you smoke,how long,your age,history
Not wearing a seatbelt while driving can result in you getting in an even worse car accident than if you were wearing one, you can get thrown from the car. Happens right away
Eating too much junk food may result in weight gain and higher risk of illnesses such as obesity. This can happen right away or overtime, depending on the person and situation, how long you do this, your age,height & history
Not exercising for atleast 30mins. per day can take time for you to gain weight, get sick easier and have a shorter lifespan or quickly, depends on the situation & person, how long they've been not doing this, how old they are, how active they are or were
It's your choice but I would say not wearing a seatbelt while driving
