I know i've been spamming it up recently, but I'd just like to add some weight to this (however small).
Recently I've been doing some 'preliminary' metta, before moving onto anapanasati, really focusing on moving that metta outwards, towards specific people and then out to the world in general, one can't help but smile, it definately brings a little pīti out to play, and it makes focus so much easier. For me it's been the like the difference of filling the car up with 91 unleaded, and filling it up with 98 super premium octane.
Hope you all have a Mettaful day.
"For a disciple who has conviction in the Teacher's message & lives to penetrate it, what accords with the Dhamma is this:
'The Blessed One is the Teacher, I am a disciple. He is the one who knows, not I." -