Why would we want to accept 'what is'? Surely we want to improve things, which involves asking questions such as 'why' things aren't working as effectively /efficiently as they could.
Another way of looking at it is to 'improve' yourself so that you better live in harmony with 'what is' rather than constantly seeking to change 'what is' based upon self centred judgements. A verse from the Tao Te Ching:
Man tries to improve the Earth,
He always fails.
The Earth is a natural harmony,
It cannot be improved upon.
Try to change it and you spoil it.
Try to possess it and you lose it.
Some things are fast some are slow;
At times living is easy, at times hard;
At times there is strength, at times weakness
There is a time to flourish, and a time for decline.
Therefore the Wise do not impose upon the Earth,
They avoid extremes, extravagance and self indulgence.