When it comes to impulsivity and self control, everyone is different. Impulsivity is when acting before thinking something through fully. Self control is the ability to control oneself, specifically ones emotions and desires or the expression of them in ones behavior. When their is a lack of self control there can be negative effects and consequences, such as indulging excess amount of foods or drugs/ alcohol. But, self control can also be positive but not only does it take will power but the though of the conflicting outcomes the action may have is enough for someone to have a lot of self control. Same goes for impulsivity, but the outcomes are typically more negative rather than positive. Acting on an impulse can sometimes feel exciting for someone, depending on the situation, but they don't usually get the outcome they wanted and this can lead to issues down the line.
In the video I linked below it talks about how ADHD can impact the brains ability to act on an impulse and lead children to sometimes not make the best choices with the best outcomes.