IME some pedals aren't sympathetic to other pedals in the chain
2 examples of pedals which are truly fantastic on their own but either overpowered or underperformed with others would be the Sadowsky Pre and the old Diamond BCP-1 ( SGFX /Diamond seem to have fixed the problem with the relaunched Comp/EQ)
A pedal I think goes great with other units is the Crowther Audio "Prunes and Custard" it seems to do all sorts of goodness with OD , Filter, Chorus. Not the easiest pedal to find but certainly worth a bo peep
What pedals do you guys like for their interaction styles ?