Sometimes, if I'm talking about something, er, tricky? nuanced? touchy? I struggle to find the word best suited to describe what I'm talking about and take a long Harold Pinter like pause to access it (let's just say it's because my inner-dictionary is a big fat book).
One thing (among many) I love about Taboo is that I can take pause to find a word and people just assume it's because I can't say the word I really want to.