If there is low or limited downside and high or unlimited upside, the situation is convex.
For example, consider you're looking for a job. If you send a prospective email to a company, asking for employment, there is asymmetry in outcomes: low downside (you risk maybe 1 hour and a bit of ego) but high upside (job).
If you promote your drawing on Reddit, you have limited downside (maybe 5 minutes of creating the post) but virtually unlimited upside (millions of views, if it goes viral).
In a convex situation, you win by repeatedly exposing yourself to randomness because any randomness is more likely to benefit you than harm you. Take many shots because you have little to lose but everything to gain. For this reason, convexity is also called antifragility: not only are you not harmed by randomness, you are actively benefiting from it.