"When unhappy, one doubts everything; when happy, one doubts nothing."

Roux is pointing out how much our mood colors the world. When we’re unhappy, even ordinary things can start to look suspicious: a short text feels cold, a small mistake feels like proof we’re failing, and the future seems full of hidden problems. But when we’re happy, we move through life with a kind of ease. We trust people more, forgive little inconveniences, and don’t overthink every detail. The quote is a gentle reminder that our thoughts aren’t always objective truths; sometimes they’re weather passing through us. Before believing every doubt, it helps to ask: is this really the situation, or is it just my sadness speaking?