Save Earth: Love it or Leave it!
The future of the earth depends on how humans feel when they interact with it, whereas Stephen Hawking famously said that future generations of earthlings will have to find a new planet if humans are to survive. But we don’t know when, and we don’t know what will going to happen to our earth first. Well, the words “Love it or Leave it” in this tee makes sense to me. Either way if you don’t love it you are definitely going to be leaving it. (Of course, how people who don’t love it are supposed to leave it isn’t specified.)