I love a nice, juicy restaurant burger, but man, are they messy. The minute you pick one up to take a bite, half a litre of burger juice pours onto your plate, making it a terrible place to set your burger down unless you've got a thing for soggy buns. Here's my personal workaround.
Normally, you only have one option to avoid a sloppy, wet mess: once you pick up your burger, never set it down until you've finished it. It's a fun game, but once you've won a few times, you realise it's more fun to play the "drink beer and eat fries in between burger bites" game.
Most places will automatically give you fries with your burger. What I suggest is you take a few of those fries and lay them out on your plate, parallel to one another, and spaced out about a quarter of an inch. This is the "fry rack," and it's where you should now set your burger.
Basically, you've created a kind of grate for burger juice to fall through down to the plate, as well as a dry platform for your burger to rest on. No more pools of burger juice, and no more soggy buns that fall apart before you've even managed to get halfway through that succulent half-pound patty.
The fries also act as a sponge to soak up some of the juice before it can even begin to flood your plate. Granted, this method calls for the sacrifice of a few good fries, but they knew what they were getting into when they signed up.
If the fries that comprise your dry fry rack (that's Shakespearean right there) start to get soggy, create a new fry rack on top of the old one with a perpendicular, crosshatching approach. You'll once again be safe from juicy burgers. Go, my friends, and eat your restaurant burgers with soft, not wet, buns and dry hands.