Tell me about mistakes you've made while playing The Sims 3

I don't have any screen shots, but there was one sim that I had created. I don't remember all the traits I gave her, but she was very mean. She was a criminal and did reach the top of her career. Her favorite pass time was to jog every where, and she lived out by the water fall in Sunset Valley. Once she became an adult it dawned on me that I better get her married to someone, so she would have some kind of legacy to pass on. But the problem was, with the combination of traits that I had given her, there was no option for any romantic interactions what so ever would should. I ended up cheating a bit to give her a slight personality change that would allow for to have romantic interactions. Eventually she found a guy and was married. At the time I did not know how to tell the age of a sim, so I had assumed he was in the same age group as my sim. I gave him grey hair, and later discovered that he was just a young adult. They ended up having one adopted daughter (which EA's story progression later moved out of town), and a son. Later the son got married, and had a son of his own. While the grandson was just a baby, his mother died. She was electrocuted, because I did not know that after the first shock, don't have them do any more work on electrical items.

Playing it on Mac :(

I accidentally locked a vampire npc sim in the University dorm and he turned to ashes in the second day XD

I used the fertility reward the first time I played and got either twins or triplets. Big mistake.

I learned about puddles and fixing broken electronics the hard way. :(

And this isn't exactly related to the game, but one of my main families back in early 2012 was this super-rich family headed by Declan...the matriarch? It took me until I was done with high school and also well-attached to that household to learn that Declan is actually a man's name.

I just remember my biggest goof up. I had started using mods, and removed the 8 sim limit per household. I started out with a family that had mom, dad, son, and grandmother. For some reason this family was very fertile, and had 2 sets of babies born, both time it was 4 babies, which ended up leaving me with 8 babies, a toddler, mom, dad, and grandmother, and a game that lagged something awful.

When I first started playing I feared multiple births. But as I got accustomed to the game I decided I wanted twins or triplets. I was using gay male couples which required a mod for same-sex pregnancy. But despite my trying, I only ever got single births.

Then I looked up all the ways to increase the chances of having a multiple birth pregnancy: listening to the kids radio station and watching the kids channel TV. I took my gay male couple I was playing at the time, and got them both pregnant. Then I had them listen to the kids radio station and watch the kids channel on TV as much as possible. I also gave them the fertility treatment LTR, the first time I had use that. Now, the mod I was using allows a 0.01% chance of quads, which wasn't apparent because in the mod settings menu it only shows a 0.00. Both guys had quads. I was floored. I didn't have a problem with the game lagging, but it was a major shock. I started to blog about the experience, but sadly never finished that particular household.

My biggest mistake was in turning that bug-fest know as EA's "story progression" on in my early days before I even knew about Mods.It was a huge disaster and I can't go into details because of the adult content rating it would have though I can tell you it totally ruined my entire game for that save and destroyed the town.I had to delete the save and start over.I also had to change from Norton to AVG so I could download Mods to fix the issues.
My most recent mistake was in adding extra trait slots using Retuner without disabling the add missing traits to sims feature in story progression.That was enough of a disaster with only two families and it could've been a lot worse if I'd already had dozens of families.
My third mistake was adding school rabbit holes to Winfield and Glenvale County which forced children and kids into that school.I should have them all in home-schooling before adding the school next time.

My mistake when WA came out was sending my adventurer sim to every tomb, collecting every relic I could find. Every urn, every dropastone, every gargoyle, she had the lot. At least three of everything, except for the special rewards. I tried to set up a private museum and quickly ran out of space so I attempted to move the family with all the relics in the family inventory.
I got the never ending loadscreen and had to quit without saving. Then upon reloading the game, whenever I tried to reload their house, I got the never ending loadscreen all over again and had to trash my save.
I really miss that save. It was so much work.
Still, it taught me a valuable lesson about not over filling inventories, and moving. Until Twallan, bless the modfather, expanded his entire suite of mods from one single SP mod, to the suite there is now, which helps a great deal.

My biggest mistake was installing Seasons. My teen sim died of starvation (?) while entering a hot dog eating contest. I decided to go check up on her dad's lifetime points to see if he could afford a philosopher's stone, only to find that he was somehow drowning after swimming autonomously in the pool because of the routing issues that the diving board always created in my game. Even cancelling the swimming interaction didn't help, and the poor dad died as well.

... And then Seasons destroyed my laptop's insides and I decided to get a Macbook to replace it, and discovered I couldn't play the game on it at all.

I hate Seasons.