Use the following trick to quickly increase your friendship to 100. In the Object Catalog, go to "Seating", then purchase the "Garden Swing". Place the swing on your lot. Select the swing, then place it in your inventory. Go to Town Square and place the swing on the lot and sit down. Call over your Sims and you will increase your friendship to 100 as long as your Sim is in a good mood. Note: You do not have to place the garden swing back in your inventory -- it places itself.