There's a mindset that I often run into with IRL discussions that revolves around the premise that if a person has some minimal essentials met by doing nothing, then they will have no motivation to ever improve their situation at all.
That if a person can afford to accomplish nothing but still have enough money to smoke weed and play video games, then all anyone will ever do is smoke weed and play video games.
I don't subscribe to that mindset: I want a nice place to live, with room for all of my hobbies and for guests to comfortably visit overnight. I want a good car and a nice place to park it and to work on it. I want to be able to afford a glorious steak dinner out or an amazing gyro without having to sacrifice. I want the best tools to create my own food in my own kitchen. I want the fastest internet and an ample homelab to do stuff with it. I want to make an annual thousand-mile pilgrimage to hang out with some friends for a week doing cool shit together (which requires real money), and I want to be able to take an actual-vacation some other time in the year where I can afford to go camping or something. I want to be able to provide thoughtful and useful gifts to my people, even if they happen to be expensive. (And if I were allowed to smoke weed [my job doesn't permit it and testing is both thorough and regular], I'd want the best weed.)
I wouldn't be able to accomplish these things with UBI, so even in a hypothetical future where UBI is a thing: I won't want to sit around and do nothing: So far in life, I want quite a lot more more than the basic essentials and I'm willing to work for those things.
(I do know some people who don't seem to be capable of more than nothing, due to mental and/or physical conditions, and it's likely that all of us know someone like this -- and these folks will have a rough time with life with or without UBI. But I firmly believe that most people would prefer staying in the rat race, because most people who are capable of work also have some fondness for whatever they consider to be *nice* things.
But I might fall down in the future; it's happened to me before for a variety of reasons. And it'd be nice to be able to afford to fall down without becoming homeless when my income drops from something useful to near-zero.)