<prompt> Human: My girlfriend and I joke about these lessons all the time, and I realized that someone else might get a kick out of laughing at my mistakes want to avoid learning these lessons themselves, so I decided to write some of them down. Feel free to add your own!1. The Windex lesson.This one was all on my girlfriend. First day in her new apartment, we went shopping. She bought literally everything store-brand, the absolute cheapest she could find. Most of it worked...okay, until we got to the Glass Cleaner.It was the worst. It streaked, didnt clean a damn thing, and we ended up going back to the store to buy the real thing. Lesson: Sometimes, it costs more to buy the cheap things, because you either have to use more of it, or you need to go back and buy better versions.2. The Organic lesson.This one was mine, unfortunately. You know those awesome giant bag cereals that are all off-brand and delicious? I had eaten those all my life, and decided: Hey, the super fancy organic cereal must taste amazing! It costs like twice as much!It was awful. It tasted bad. It smelled bad. It didnt soak up the milk, so it was like eating rocks. After the first half-bowl, that box sat in my pantry for about 6 months before I finally admitted my mistake and threw it out. The worst part? When I actually compared the nutrition facts, it wasnt even much better for you than my cheapo Fruity Dino-Bites. Lesson: A high price tag doesnt necessarily mean its better.3. The Convenience lesson.Also me. Dammit. This one is me forgetting to properly plan for our vacation. We went to Hawaii. I didnt pack sunblock.Sunblock at our local Wal-Mart? Like 3. Sunblock anywhere within a 20 mile radius of our hotel? 17. Lesson: be prepared. It costs way more to buy things you need where you need them, because, chances are, demand is super high there.4. The Travel Site lesson...Also me. A theme is starting to develop. No one mention this to my girlfriend. This one was also from our vacation. I booked on one of those travel websites that gets you awesome deals on hotels. We booked this awesome undersea tour for about 80 a person. When we got there, we saw the pricing sign. It was 69 a person. That rate was also available on their website.It was still an awesome activity, but I could have saved 22 just by paying for that separately. Lesson: Do your damn research. Dont immediately buy something just because you think its neat. 5. The Landlord lessonThis one was my girlfriends fuck-up! Ha! Our landlord has you pay with checks or money orders. Well, she didnt have a checkbook, so she would go and paid 3 for a money order from the local convenience store. She threw away the bottom copy, because shed never had any trouble paying her rent before. She always just wrote her name on the envelope, and the landlord knew where it went. Well, the landlord threw the envelope away without looking at it this time. She got a notice of non-payment on her door the next day, and we had zero evidence that shed actually paid. Turns out, a bunch of people use that same place for money orders, and a few of them also hadnt paid. Her saving grace was the fact no one else came to claim the unlabeled money order. Lesson: Keep your pertinent documents regarding any major transaction, or even minor transactions. Your landlord has no duty to keep your records for you, and other people make mistakes sometimes. Also, make your signature recognizable. A squiggly line does not a signature make.6. The Terrible Car lesson.This one is my fuckup. I decided that I would empty my savings, including my e-fund, to pay for my last semester of community college, because fuck student loans, amirite?Then my car broke down. The timing belt snapped and bent every valve stem when it did. Total cost was 1600 to fix it. I had no way to pay, and I was looking at using my credit card to pay for it. Thats a 22 interest rate. Basically, instead of taking a 4 loan, I left myself with no way to pay in an emergency and was almost forced to take out a 22 loan so that Id have something to drive. My grandfather stepped in and saved me with a 0 loan, but that could have been really, really bad.Lesson: This sub harps on an emergency fund for a very, very good reason. You have no idea what will happen to you next month, tomorrow, or even in the next 6 hours. Not everyone has an awesome grandpa to step in and save them from drowning financially. A lot of these, in retrospect, seem like common sense. When I was 20, just starting out into the world on my own, though... not so much. No one had bothered to teach me, and honestly, I thought I was way better prepared than I was, so I never sought out help. Im 26 now and in a decent financial position, with an excellent credit score and a good job, but some of these fuck-ups could have done a lot of damage. Hopefully this does more than give a lot of the rpersonalfinance old-timers ammunition to make fun of me. If there are any teens in this sub, be warned: you will likely think youre smarter than me that might even be true, but there are a host of financial problems that you wont see coming. Take any advice you can get.  <response>: We have all been there, and not many people will want to laugh at your distress. Emergency funds are for things that break houses, cats, cars and for things that leave health, job, spouse, and most of us never see those events coming. So you have not only the expense, but the trauma of the triggering event. Yeah, weve all had that heartache. 