烦

Left fire radical - the indexing component. Pictures flames rising with sparks flying out. Captures the burning, fevered feeling of irritation that 烦 describes - the head feels hot, things grate, frustration mounts. The radical placement (left rather than the bottom 灬 'fire-feet') keeps the fire upright, as if heat rising in the face.

Right 页 - originally pictured a human head (the simplified form of 頁; same shape appears in 颈 'neck,' 顶 'top of head'). Combined with 火 on the left, the whole character is a compound ideograph: a head on fire, a feverish, frustrated mind. From that vivid picture come the senses: vexed, annoyed, troubled, bothered.