I think you need to have a few of those "I've use this pattern and had to stay up 24 hours to meet a deadline because shit was way too complicated for the delivered value" to instil a healthy fear of overcomplicating solutions.

I've worked with developers with 5+ years of experience that haven't went trough that (either corporate culture allowed them to deliver minimum value in 5 days or jumping projects before it gets to the WTF stage of complexity). It's hard to learn if you never get burned.

Experienced and exposed to areas outside their main expertise so they are well rounded and pragmatic.