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To say no to things I don't want to do.
That other people don't care what you think. They're more worried about themselves, and you aren't the first thing on their priority list.
Could've saved so many headaches if I knew this years ago.
To save money. Now I'm always broke and I never have enough money for a back up plan.
That the 'someday' you are waiting for, (you know, the one when your real life will start to happen) is happening right now.
Don't wait to do the thing.
If you let people take advantage of you they will.
Should have stayed in shape.
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You need to force yourself to socialize. Don't isolate yourself.