lack d creativity

just got out from the 4sc class..i was teaching them the same thing that i taught form 4a just now..we were brainstorming about playboy for the poem he had such quiet eyes..then after hearing their responses, i realised they lack the creativity as compared to 4a..i don't know why..could it be that they were just too serious to give playful answers (but some of them were quite crazy, really) or maybe they were just too little of them..there were only 14 students in that class, which was quite small number if to be compared with the 30 students in 4a..so i couldn't really blame them..