Why is hydrofluoric acid a weak acid? (or rather, why is its dissociation rate so comparatively small?)?

I don't quite understand why the dissociation rate for hydrofluoric acid is lower than for the other halogen acids (HCl, HBr, HI). I would've thought that HF would /want/ to dissociate since fluorine is so electronegative...wouldn't it want to take that electron for itself?