I was told a very long time ago to never sell something short because you have the risk of unlimited loss. But another drawback, from what I read, is that sell

I was told a very long time ago to never sell something short because you have the risk of unlimited loss. But another drawback, from what I read, is that selling something short is taking out a loan, and if something is obviously a very lucrative short, then the interest will usually cancel it out. Free lunches exist, but if it seems really obvious, don't get your hopes up.