This comic is funny because it sets up a very serious, mature, and philosophical expectation, and then completely subverts it with a shockingly honest and slightly unhinged punchline.
The first panel makes it sound like a deep reflection on aging: as you get older, society lowers its expectations of you. You are no longer pressured to be impressive or productive. This sets a calm and melancholic tone. The dog is sitting peacefully at a desk, looking out the window, which feels very contemplative.
The second panel continues this wise, self-reflective mood. The dog closes its eyes, appearing deep in thought. The phrase "岁月的洗礼让我逐渐认清了自己" suggests that through life's trials and tribulations, the dog has finally gained true self-awareness. The reader expects a conclusion like "Ive learned to be calm, compassionate, and at peace with myself," or that the dog has become more mature and serene.
Then the third panel hits with the punchline. The dog's eyes are wide open, bulging, and it looks completely unhinged and freaked out. And the "self-knowledge" it gained is that it has become "更反复无常,更加不耐烦,更真实" - more fickle, more impatient, and more real. The supplementary text emphasizes "更真实" with a cute but manic face.
The humor comes from a few places. First, it is a massive bait-and-switch. You think you are about to receive a profound quote about growing old gracefully, but instead you get the confession that aging just made you a grumpy, moody jerk who has stopped hiding it. Second, the visual contrast is hilarious: the dog goes from a serene, thoughtful sage to a freaked-out, bug-eyed gremlin in one panel. Third, there is a deeply relatable truth hidden in the joke. Many people find that as they get older, they care less about social niceties and become more openly irritable and impatient. People expect less of you, so you feel free to just be your grumpy, authentic self without apologizing for it. The comic uses a cute, innocent-looking dog to deliver this extremely petty and cynical confession, which makes the contrast even funnier.