I love how the captain's logs give Olimar a bit more personality beyond being just a goofy little character. He's surprisingly eloquent and introspective, and I especially like his dialogue after a Pikmin extinction:
“The Pikmin have all perished because of my own carelessness. I am an utter disgrace as a leader... How can I continue to collect parts without them? Still the Onions join me in low orbit, as if this Pikmin extinction had never happened. I shan't sleep tonight...”