Do we have control of thoughts?

I watched a video of the Dalai Lama and he seemed to be saying that afflictive thoughts cause suffering and that people need to control their thoughts and cultivate wholesome ones etc. Outside of a retreat environment I can't see how it's possible. Everything is moving so fast. Hundreds of thoughts are just coming and going all the time. It's not even possible to be aware of them most of the time. I find myself suffering and have no clue about the thoughts that got me there. I mean they must have already happened and gone. It's not like I chose to think them. I'm not sure what I should do. Should I just try to cultivate more metta? Also we are taught to not analyse the content of thoughts arising during meditation but to just note them and return to the breath. I'm wondering how I get to know what is wholesome and unwholesome if I don't analyse?