How worried Rincewind was when Twoflower was poisoned by the druidís sickle.
When Rincewind sees Twoflower heading towards the tower to stop Trymon he instinctively goes after him.
It may not mean much, but this Troper thought it was sweet to see Twoflower try to help Rincewind against hide Trymon. And then when Trymon turned on Twoflower Rincewind attacked him before he could do anything to the tourist. Although this could have been just because it was the only opening he had, but still.
The luggage protecting Rincewind from the mob.
When Twoflower and Rincewind say goodbye. While it doubles as a tearjerker, itís so heartwarming to that after everything they've went through together Rincewind really will miss the tourist.