Stupidity: Friend Request: Michael sneaks into LifeInvader as an IT temp so that he can plant an explosive, which he is carrying in a blue bag, into the prototype mobile that Jay Norris is going to use. He leaves the blue bag, evidence tying him to the explosive, in the LifeInvader building.
Stupidity: Franklin actually knows that the house used by the tennis coach to hide is indeed someone else's. The funny thing is that if Franklin told Michael that it isn't the tennis coach's house, the two won't tear down the house, leading to all sorts of conflicts. They won't be found by Martin Madrazo, which leads to the Jewel store heist or be found by Trevor, etc.