A cook I know always discards the core of the onion when chopping it. Is there any reason for this? In professional demonstrations and cooking classes, I've never seen it done. From observation, it does seem to make chopping or mincing the way I've always been taught a bit easier, as the core can be awkwardly shaped, but other than that is there anything besides personal preference to it?
The core makes you cry much more than the rest of the onion, if you're prone to tears. There's actually already a question about onions and tears, with an answer explaining this.