In the past I would be more casual with my use of terms like 'gay' or similar as a playful insult amongst friends or acquaintances, but am more cautious about usage these days out of fear of causing unintended offence. That said I still use the term in trusted circles today, but we've become a bit meta in how we joke about it, e.g. "Don't be so gay .... not that there's anything wrong with that these days of course!" with the disclaimer being an enjoyable part of the banter now.
Overall, I don't think I've had any publicly held opinions in the past that I'm now embarrassed by. I do have some beliefs that I expect would be different to that of the majority, but I have never and would never share them publicly because I accept they would likely offend or be misunderstood and wouldn't serve any positive purpose so I'm far happier keeping them to myself.