What determines manager interaction options?

Just a quick question about manager interaction, whether just randomly through their profile page, or during the build up to a match.

Often, it will have a long list of options, under varying headings (mind games, positive, negative). But many times, only a limited number are allowed (sometimes only one). Does anyone have an explanation?

It is not like I am dissing an obscure coach in New Zealand, that I suppose realistically I would have very little to say about; As Arsenal manager, I am surprised that I only have the option of one negative comment to direct at my Chelsea rival, for example.