I stop doing things I don't care about.

If it's low motivation to do my job, I look at why. Am I tired? Do I dislike the kind of work? Does it feel like it's not going to help?

First, I make sure I'm actually doing alright. Usually, I'm just tired or maybe sick. Then I'll raise my concerns to management. There's a good chance that I'm not working on something meaningful and that we should change that.