The reasoning?
I think that in this context Paul was warning the Philippians against complaining that led to divisions within the Church. But, what does complaining ever achieve? Is it ever useful for building up and encouraging one another? Does it ever inspire greater unity? You could argue as Job did (in Job 6:5-6)
Don’t I have a right to complain?
Don’t wild donkeys bray when they find no grass,
and oxen bellow when they have no food?
Don’t people complain about unsalted food?
Does anyone want the tasteless white of an egg?
And in context the argument would perhaps be just. There are times when we need to release emotions built up inside and a good rant can be quite healthy. But, use caution when choosing who you rant to. Rant to someone who keeps you reasonable. Don't rant to someone who encourages your anger or depression.
Anyway... the first weekend of no complaining was actually pretty easy, but I also wasn't too stressed and didn't have much to complain about. Beginning the next week it became a little more difficult. No more, "arg... I hate chemistry labs..." on Monday mornings and no more "Why is it still snowing!!"
The result?
When I stopped complaining, I stopped focussing on the negative and began looking for the positive (especially when I was caught complaining and tried to cover it with some positives). It always bothers me when people complain a lot and so I was glad that I wouldn't have to bother others with meaningless complaints. Ceasing the complaining forced me to change my perspective and to focus on the positive. And that's enjoyable.
Lately I've been forgetting my attempt to quit complaining and it's been sneaking back in (especially in regards to the long, cold winter weather). So, here's reminding me again,
"Do everything without complaining and arguing, so that no one can criticize you. Live clean, innocent lives as children of God, shining like bright lights in a world full of crooked and perverse people. Hold firmly to the word of life..." (Phil 2:14-16)