One of my favorite Sim couples had a wedding. A lot of Sims were getting drinks at the bar and the bride and groom were there too. I had the task to make Sims flirt three times, so I made the bride flirt with the groom and I queued the action three times. Then I noticed that the groom was very angry. I had accidentally clicked a wrong Sim because there were too many Sims packed in together. The bride had flirted with a random guy and I tried to cancel the actions from her queue, but she had already done it twice and refused to cancel the last one. Oops. :#
The wedding was a disaster. The groom was angry and then sad for the whole time. Their relationship bar took a huge hit and cherry on top... the random guy (that the bride flirted with) showed up later and flirted with the bride and of course she flirted back, with her newly wedded husband standing next to them. I had to spend a lot of time to fix their relationship.