I love writing first sentences. You get to write the hook without having the pressure of where to go next. The first sentence is the beginning of creation. A good first sentence captures the writer’s inagination as much as the readers. 

I find writing the first sentence easy. (Although it may not survive the editing process).

Here’s a few first sentences for a Young Adult story (that I’m not writing):

• My dog has magical powers. (This idea came from an image on Diedra Alexander’s blog)
• The first time I realized I was different was when I got a cold: my snot was blue. 
• a flush of clammy warmth ran through me with that sense that I was about to throw up.