DO NOT UPDATE PYTHON ON UBUNTU

Just like the title, I want to tell you , don't update python on Ubuntu by ,yourself.
But you can update it by "apt-get update" or "apt-get upgrade".
I've struggled for over 30 hours to make my python work, but I failed and just rebuild my system a few minutes  ago. I didn't know why it didn't work well when it been updated.

The fellows are what I did(including the reason and result).

When I open the Go-agent, it always uses a lot of CPU, and I think it's the python's false,maybe the python is out of date.So I just download the latest python(3.4.1) and put the source code in "/opt/pytho-3.4". Then I started to install it. You know, the normal way to install a third-part software on Linux.
"$./configure         $make         #make install"
But, it's the beginning of my nightmare.
-------My go-agent didn't work.
when I run python, it told me  that I should install python-gevent and python-gtk2.
But these two packages ware installed before! I can use it minutes ago!
I didn't study python before and I was puzzled.
At first I think it's the python3.4 because python2 and python3 are different(of cause not the name). So I install python2.7.8----no use.
After a long time surfing the Internet to find a solution.I thought it might be the environment.
Python2 and Python3 confused their environment and can not find the packages belong to them.
But when I tried to remove python3, the computer told me that the softwares rely on python will also be removed.(Almost all of my software!!) WTF!
Why does it so complicated!
I give up this way.

And I tried to correct the environment.

The user's environment are located in "/home/their name/.bashrc" file.
You can change your software environment by just adding some words at the end of the file.
For example, if you want to change the python path, you can add PYTHONPATH="/usr/local/python2.7:" and then the python will find its packages in /usr/local/python2.7  (WARING it's just an example, do not do this in your ".bashrc" file)
When I added some path to PYTHONPATH, it works a little....But also has some errors.
It drives me crazy!

And I decided to reinstall my Ubuntu system.
Back up the data, make a install U-disk and reinstall.

WTF!My tools and environment! I have to reinstall them too!!!!

No zuo, No die, Why I try!!!!