There is indeed a Quid Pro Quo with flight following: you're adding to the controller's workload, and they may ask you to do things to help alleviate that workload (like not flying through a busy approach/departure corridor).
Some controllers will also vector you around a hot MOA (even though you can fly through it VFR their normal operating mode is for IFR traffic) while others will simply alert you that the MOA is hot and leave it up to you to decide how to handle that.
Because there's no language in the ATC manual for "Hey could you please fly around this area so you don't make my job harder?" when controllers want to ask you to do something they use the language they do have, which takes the form of instructions (vectors).
As a pilot you should remember that vectors are the opening round in a negotiation: If a controller gives you a vector you don't like you can always ask them why, and often you can negotiate for something better.
This is true for IFR flights as well - The only exception is when a controller uses the word "Immediate" or any variation thereof (then you do what they say and ask your questions later).
If you know you'll be flying through an arrival or departure path you can offer to change your altitude to stay out of the way. Your handy VFR Sectional or Terminal Area Chart shows some of the arrival and departure paths for busier airports:
If you offer a climb or descent controllers will usually tell you what altitude they need you at so you aren't in the way, and if they're not forthcoming you can ask ("What am I being vectored around? Can I go through at a different altitude?").
Finally remember that as a VFR flight you are under no obligation to accept their vectors in Class E airspace: If you don't like what the controller is asking you to do and can't negotiate something better simply say
We'd like to cancel flight following at this time and continue on your own navigation (keep listening to the frequency to see what they do and maybe you'll come up with better alternatives for your next flight).
The controllers may grumble about it, particularly if they just put you into the system and you immediately cancel services, but that isn't your problem.