1. Losing the ability to eat whatever the hell you want with impunity and feeling no side effects or noticeable weight gain, along with a relative amount of toning over the entirety of your body even though you literally never work out.
2. Taking dates and relationships more seriously because you are finally in that phase of your life where you could actually envision yourself getting married to someone down the line, whereas you were always able to brush it off with something along the lines of "It's not like I'm going to get married, I'm way too young for that."
3. Becoming acutely aware of what it is that you're doing for work and how that relates to the studies and skills you paid all that money to acquire. (Likely it doesn't relate that much at all, and makes you feel markedly bitter about all those people who insisted how useful "Poli Sci" was going to be.)
4. Forcing yourself to start enjoying all of the foods you had once written off completely as "gross" because you know that they're good for you, and directly related to how good you're going to feel throughout the day. Yes, spinach and broiled fish, I'm talking to you.
5. Becoming markedly less insecure about all of the things which used to torture you in adolescence, such as whether you are wearing the coolest brand of jeans. (You know that you can't afford those jeans regardless, so it doesn't even matter if people think they're cool.)
6. Learning to temper the existential crises you go through when you are referred to as "sir" or "ma'am" by kids who aren't even that young.
7. Realizing that the vast majority of people on your Facebook are now what you not so long ago would have considered "old," and doing "old people" things such as buying homes and having children -- even though you always imagined you would be off of Facebook the second those kinds of things started happening.
8. Talking to your parents and noticing that you are, in many ways, addressing each other as equals in a way that never used to happen. (That is, unless you are asking them for money or some other favor, in which case you are about five years old again.)
9. Understanding much more quickly who is right or wrong for you in a romantic sense, and not being as willing anymore to stick around with someone who clearly doesn't make the grade.
10. Getting more and more brave when it comes to deleting people from your phone/friends list/life in general when you are just getting tired of them being around you and can feel that they're dragging you down.
11. Becoming more acutely aware of how precious all the time you have with your older family members is, and how not a single day with them is guaranteed.
12. Making yourself a more financially-oriented person, even if you don't have that much capital to work with at any given time. (No matter how much you're earning, you know that there is always a better way you could be budgeting it, even if you don't want to admit it.)
13. Learning about multivitamins.
14. Investing a blender and learning about all the various magical properties of the Domesticated Smoothie. Even if this means spending a significant percentage of your income on fruits, greek yogurt, and powder supplements.
15. Coming to understand that breakfast, no matter how many years you completely ignored it as a meal, is essential to having a productive day if you have to get up early and regularly and be active for the entire day.
16. Learning what it means to really need sleep on a regular basis, and how precious those nights when you can comfortably get to sleep at 9 PM are. (This also includes using a moderate portion of your weekend time to sleep on a semi-regular basis.)
17. Being more conscious about the presence you allow to display on the internet, when you used to be the person who blogged "artsy" naked selfies and wrote every gory detail about the person you were sleeping with that week. (And had at least 20 percent of Facebook photos taken while intoxicated and/or holding some kind of drugs.)
18. Leaving places much more easily when you are not happy in them, including house parties, restaurants, and stores you know you cannot afford.
19. Accepting that some of your purchases are just going to have to be quality, even if spending more money up front really makes your stomach hurt and ignites your ever-present-if-dormant "cheap asshole reflex."
20. Getting out of the phase of your judgment where things that you don't immediately recognize make you recoil in disgust. Side effects include trying scary-looking seafood, deciding to meet some of your coworker's friends for happy hour to expand your social group, and signing up for a salsa class.