Usually the goal of UBI is to lift everyone above the poverty line, not to make everyone's lives comfortable.
If you're happy living as a lazy fuck just shy of poverty, you're welcome to do so. If you want some comfort, security, and the ability to not anticipate each 1st of the month, you'd probably still want to work.
I personally think that UBI is a requirement for us to be able to say that we each have a fair shot at success. Nobody should worry about having a roof over their head or providing food on the table. We have plenty of both for each human in the world already.