The big obvious one here, as EP has said, is people being overweight.
The pressure obese and overweight people put on the NHS with their associated ailments is absolutely huge. Do they have an obligation not to eat so much, I'm not overweight, why are their choices impacting on my freedom to get timely healthcare?
Should we ban fat people from eating fast food? Or exclude them from society altogether? After all, the evidence is out there for people to see how damaging to health their health it is, yet they carry on regardless!