I'm hoping on buying a multieffects pedal today, but I'm not really sure what the best way would be to choose one. Should I just sit there and mess around on every individual effect, or should I focus it somehow? Are some effects more essential/finicky than others? What songs/styles should I try it out on?

What are some common problems with multieffects pedals as well, even if it doesn't have exactly what I need I don't want to buy a faulty effects pedal. Thanks for whatever help you can think of, as I'm nothing of a gearhead myself.
Go to Guitar Center and just play with them all. You'll find something you like more.
My Gear:
-Schecter C-1 Plus (Vintage Sunburst)
-B-52 AT-212 Tube Combo
-ZW-44 Zakk Wylde Overdrive
-Digitech RP350 Multi-Effects Pedal
-Hamer Slammer Strat Copy
I haven't had many effects before, so I won't know how to "just play with them" unless I spend a very long time on each pedal. What do you mess with/play around with when you're trying them out?