On what ground do you reject tasks the most?

[Btaliat]

There is nothing bad in freelancers rejecting tasks. In fact, it is very common. But there should be a tangible reason for this. For instance, you should omky reject tasks when you know the tasks are too technical for you. And you may not handle them. If you know yo are busy, and you are likely not to meet up with the deadlines from the clients, you can as well rejects. If the payment is small and you don't want to price yourself low, you can also reject. On what basis do you always reject tasks?