Why not a weak password, why not never?

I am not a Linux ninja, nor even a tech ninja for that matter, but I am fairly old on Linux and growing older with it. I love this thing. Have been using Ubuntu for like 5 years now after briefly trying many other distros with an on-and-off fascination for a MacBook Pro till now. And yes, I play CS 1.6 so I dual-boot with 7 at home.

Recently, I was very disappointed when I was not able to to set a password of my choice on Ubuntu (I tried on many other distros after that)

It returned this, even after I tried repeatedly:

Weak password: not enough different characters or classes for this length.

passwd: Authentication token manipulation error

passwd: password unchanged

My current password is "riro@123"("riro" is abbreviation for my organization) after I changed from what the Sys-admin gave me the system with, the deafult for everyone "user123" ("user" being the user and it enver changes, no one does), and for the sake of ease (it's a PITA to type that "@" with SHIFT and all, trust me) I want to keep it like "123" or "abc" or heck I just want to keep it "1" or "a" or so-so blah-blah. I am not exactly explaining why but the computer is not connected to the Internet. No one outside my team has access to it. Almost everyone in my team uses similar and easy passwords as we need each other's Linux PCs for build and other purposes regularly, in their absence too. I have to fire up frequent SUDOs too.

No, I mean I could have wanted to do the same even if it was connected to the Internet with all my bank user names and passwords in plain text kept in "~/Desktop". So what? This is my computer and my Internet connection and I have got every right to screw myself. Who the hell are these Open Source people to tell me that my system should not be that easily openable! I just want a password I want.

I just easily wanted to set an easy password on a system that is not importnat from the security point of view.

PS. I use LastPass for all other purposes(yeah I still trust LP guys, mainly because it sysncs my password online and works everywhere seamlessly :P). I am pretty much secure, as of till now.