I can sell call options 10% out of the money each week and make some nice cash. If my plan was to hold the stock long term, there's no downside risk because if the stock goes down, I get to keep the cash (premium) from selling the calls. If it goes sideways or slightly up I get to keep it as well.
The only "downside" is it goes up >10% in which case i've made that 10% + premium, but I've now had my stock taken away from me.
In this case, I lose out on an additional 10% in upside because it went up 20% overnight.