Worst I've had was a brittle 906 lamp crumble apart in my hand while shopping out a Striker Xtreme. I believe it was the one behind the white oval insert on the backboard of the playfield with GOAL written on it. The plastic was melted so the bulb was likely locked on at some point or on for a VERY long time. Took a few minutes for the ER nurses to dig all the glass out of two of my fingers.
Ironically several years later that same game tipped over during transport. Nothing bad happened to anyone or the game, just a little black paint missing off the back. Of all the games I've moved over the last 21 years that's the only machine I've had happen to me.