My Jiggly Ball and the His Story from Kelso's perspective (is it IV? I always forget which is which) probably highlight who Kelso is better than any two episodes in the series. Kelso comes across as heartless because it's much easier to let everyone hate him for making the hard decisions than trying to make everyone like him. Kelso is all about distancing himself from the pain and getting emotionally attached because it makes it easier to make the difficult decisions no one likes or wants to make. It's why Kelso becomes so much more personable after he resigns. He doesn't have to worry about that stuff anymore.
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"I couldn't stand a day without a past or future. I need to live each moment to keep fighting here and now."