Sympathetic is a ‘false friend’ for people who speak European languages. It does not mean the same as sympathique, sympathisch, sympatisk, simpaticoetc.

    The people in my class are all very nice/pleasant (NOT . . . very sympathetic.)

Sympathetic means ‘sharing somebody’s feelings’ or ‘sorry for somebody who is in trouble’.

    I’m sympathetic towards the strikers.
    She’s always very sympathetic when people feel ill.