The value of life is ultimately negative because any positive experiences will always be outweighed by suffering which is a more powerful feeling.
Fallacy Of False Cause
Aside from the notion that suffering is more powerful that "any positive experiences" -- a vast and very subjective generalization -- suffering itself is not established as 1) having objective value beyond context, or 2) serving as a primary means to measure life's value in the first place. The first objection means that suffering is relative, e.g., "the first-world problems meme." The second objection calls into question the idea of suffering as a measure of value.