My first DIY was changing oil on my beat up Volkswagen Golf (this was back in 1996 when there was no internet to find exact specs of cars). I had to return to the auto store three times to get the right socket to fit into the oil plug. After successfully removing the plug, draining the oil and refilling the engine, I did not know what to do with the used oil. So, I did what every rational person would do: poured it into the toilet and flushed it. This did not go very well. The oil stained the bowl, and had to use Ajax to brush it off. I was so fearful the house owner would find out, and kick me out (I was renting a one bedroom apartment in a multi-family house). The trips to the store, changing the oil, and cleaning the toiler bowl took around three hours. Then, I drove the car to test drive it. I got on the expressway, and it started to pour. The road became flooded, and all the cars were stuck on the highway. I had to wait to three more hours for the flood water to subside before the highway patrols allowed people to drive. By the time I got home, it was 10:30pm.

Lessons: 1. Don't pour used oil into the toilet bowl.
2. Find out the exact size of socket plug before you buy it.
3. Stay away most flood roads when it was about to rain.