How to change a sim's mood?

Thanks @vanilleonsims I did not try MCC, only read a little about it and concluded that majority of its features I won't use. But I'll check it again. OR - I will need to base all my movies on natural expressions and random moods, making it quite the challenge to record specific scenes. I'm not into poses anyway, so my stuff ought to be a bit random anyway. Some can be rescued in the editing, hopefully :)