So here we are again!
Okay, First up, I can't pick up thoughts, some people read minds but most psychics (at least the one's I know) don't read minds, they read the energy of the situation.
I'm not sure what your asking but I'm going to assume that what the client is asking is for you to pick up on the thoughts of another person?? There is something called third party reading which means that the psychic is being asked by the client to read another person. This is generally something that most psychics don't do because we only read the person asking permission to be read.
However, there is a way around this by reading the energy or dynamics of the relationship. You're not exactly reading the other person but you can pick up on the overall energy of the relationship between the third party and the client.
So, back to the question - thoughts are not that relevant. A reader friend once said that a client could ask "is he thinking about me" and even if the answer is "yes" what's the point? We have millions of random thoughts a day but they don't necessarily determine what thoughts the person will act upon.
Generally psychics are looking at the overall energy, not specific thoughts.