You just gotta love those chitta vrittis, don't you? They're adorable. They even sound adorable. Just try and say it - "chit-ta vrit-tis." Sometimes they get treated like the enemy though like, "we gotta get rid of those chitta vrittis at any cost - let's blast 'em."
Some of you are wondering what a chitta vritti is. Let me briefly explain. Chitta is like the field of your mind where all kinds of thoughts can happen and the vrittis are like the thoughts or the waves that show up. Some of those vrittis are disturbing and some of them aren't. So yogis want to regulate the thoughtwaves or the vrittis so they don't disturb us, so we can do what we want to do and think what we want to think, which for a lot of yogis is nothing itself.
Or we want to concentrate on something or see the truth or experience ourselves, and if there are a bunch of disturbing vrittis in the way or even if they're not that disturbing but they're blocking the view, then we want them toned down or moved aside or even blasted away.
One of the things with the mind is that has a lot in common with the breath, for instance we don't have to think about breathing at all and we can let it do its own thing and we'll get by, however, we can also adjust our breath and enhance certain states (like health - but really I meant states of mind). Same thing with the mind - it will go on and on by itself, but we can also watch it and guide it on purpose, never really getting rid of it, but guiding it. Sometimes we can suspend the breath for periods - we can do that with the mind too - just suspend the thoughts or the vrittis. So the mind and the breath have a lot in common. Both can be monitored and adjusted consciously or they can be left on their own and will function unconsciously.
So if you're in a state where you've noticed your thoughts or your vrittis and they're bothering you or even their existence annoys you, one of the first things you can do is find them adorable rather than objectionable. Just don't be so against them.
The second yoga sutra in Patanjali's yoga sutras is "yoga chitta vritti nirodhaha." Swami J's definition goes like this,
1.2 Yoga is the control (nirodhah, regulation, channeling, mastery, integration, coordination, stilling, quieting, setting aside) of the modifications (gross and subtle thought patterns) of the mind field.
(yogash chitta vritti nirodhah)
and he's got a lot more to say about it all on his website, which I recommend you check out over and over again!