A checklist for your twenties

Break up with a guy you've been dating/casually seeing just because they are too nice. They actually call you when they say they will, they don't break dates, they don't try to have sex with you on the first date, they aren't talking to other girls, they hold the door open, and treat you with respect. So naturally, we're just not that into him. (You will outgrow this, hopefully sooner than later)

Lose 1-2 good friends

Switch jobs a few times

Move to a new city

Participate in a long distance relationship (But remember, as I've been told many times) have an end in sight because otherwise the distance will ruin you. Fact.

Go through a big break up. Have your heart broken

Get rejected by at least one person you wouldn't have wanted to end up with anyways

Kiss someone just because you can

Secretly hate that the "bad" things still feel good

If you're a guy understand that your girlfriend, no matter how loyal she is, is not just dressing for you on a Saturday night. Hate her as much as you want for it, but you won't find a girl in their twenties that this isn't the case. She'll want to look good for you, other guys, other girls, and hopefully herself as well.

Spend a ridiculous amount of money that you don't have

Stay involved in a destructive relationship

Be a pushover

Be a huge bitch

Dress slightly slutty on a girls night out just for the simple reason that there's only a few more years left where it will be socially acceptable.

Be spontaneous: this is the one time in your life you won't have 3 kids, a house to pay off, etc. so take advantage of it. Do whatever you want at this point in time, regardless of what others think. Be selfish and do what makes you happy, because that's what being in your twenties is all about. Once you've completed the majority of these things, you are free to turn 30.