When you're caught outside during a thunderstorm, it's tempting to hide under the first big thing you see. We feel safer when we're not exposed (and being pelted with rain). But taking shelter near a tall, isolated tree or a telephone pole is a terrible idea.
The lightning we see is created when charges in storm clouds work their way down to Earth in search of oppositely charged objects. The first attractive opportunity on the way down, or what looks like the easy path to ground, just might happen to be a tall tree full of sap and water. (The fluids make it a great conductor.)
If you're standing next to or underneath the tree, you're automatically voted second place in the lightning popularity contest. The lightning can strike the tree and jump to you (a side flash) or travel through the tree you're touching and into you (contact potential). Plus, you run the serious risk of getting hit by a falling object once a bolt has made contact.
Our next worst place is all fun and games -- that is, until the sky lights up.