I have 3 supervisors, two of whom have been very helpful and supportive throughout my PhD. The third (technically my secondary) has been pretty unhelpful and absent over the years (doesn't come to meetings, provides little feedback on my writing outside of affirming with what the others have said, completely checks out of discussions regarding the methodological details of my work, largely unsupportive/uninterested in the project, etc).
In my acknowledgements I would like to include a personalised and heartfelt thank you to my 2 engaged supervisors, but it is difficult to do this without also having to include some disingenuous thank you to my crappy supervisor.
As I am nearly done with the thesis it would be silly to kick up a fuss about the quality of supervision now. Should I just include a generic thank you to all three supervisors as a collective?