As the saying goes, no risk = no reward. It's easier said than done, especially when you have bills, family, and others depending on you. Security is usually preferential to risk, and if it ain't broke, don't fix it.
But truthfully, nothing is guaranteed. You may work 30 years at a company and still get laid off right before retirement. The boss may have been embezzling the whole time and now the business has no money. The perception of safety, and the reality of it, are very different.
As jobs, bosses, and opportunities come and go, none can steal what you have learned. What made you valuable to the last company will make you valuable elsewhere. Learn from your mistakes, and the mistakes of others. Glean from those who have gone before, and be always teachable.