Why so tough?

I've been spending the morning weeding and it is strange that the plants we cherish, and value take nurturing, work and effort.
While on the other hand all the darn weeds flourish and come up without any effort or caring.

This is directly paralleled to life. Those things which matter take effort. If you have to work for something then it is most probably of value.
Those things which come easy and without much effort generally.

As Thomas Paine said: "What we obtain too cheap, we esteem too lightly: it is dearness only that gives every thing its value. Heaven knows how to put a proper price upon its goods;".

No need to fear the difficult, it just means it's of value.