These are for big mistakes. The other mistake people consider huge is huge amounts of debt. I’m on the fence about this being a huge mistake because it’s so manageable. Plus we don’t have debtor’s prison, so it’s still not as bad as jail.
Now on to the common mistakes.

Watching porn excessively
Masturbating too much.
Having sex with strangers.
Having unsafe sex.
Never asking for help
Getting involved in extra-marital affairs.
Eye up girls/boys on a regular basis.
Spending huge amounts of time on social websites.
Randomly browsing the Internet.
Too much dependence on Google search.
Confining to his/her comfort zone.
Chasing girls and money.
Choosing wrong life partner.
Avoiding meditation.
Wasting too much time on the internet without doing anything profitable with it.
Not doing physical exercise.
Not reading books.
Choosing wrong career path.
Chasing fame and power instead of vision and excellence.
Satisfying everyone.
Not using smartphones wisely.
Not studying.
Becoming a work addict.
Spending less time with family.
Neglecting the old friends.
Procrastinating everything.
Smoking cigarettes and taking drugs(Cocaine,Heroine,Marijuana).
Neglecting parents at their old age.
Trying to be a 'nice guy' all the time.
Getting in a toxic relationship.
Overlooking depositing money every month.
Drinking too much alcohol.
Wasting money to buy luxury but unnecessary stuffs.
Giving top priority on physical appearance to choose life partner.
Taking suicidal attempts after break up.
Imitating porn on bed with girl friend/boy friend.
Trying to be a perfectionist.
Taking life seriously.
Failing to accept limitation
Hate other religion except your own.
Involved with one sided relationship and love someone desperately,Who does not love you back.
Being emotional rather than practical for taking important decision in life.
Playing too safe in life.Example- Staying in job or relationship you don't like,less fun or adventure, procrastinating to chase your dream.


http://cliqtips..com/2016/10/common-mistakes-people-make-that-ruin.html?spref=tw


You can add yours.