Or if I am bustling with joy because the wife and I managed to sneak in an evening of kinky sex between bringing the kids to bed and work on monday. THAT's what I am thinking about and THAT's not what I want to tell you. So I invent some stupid story just so you are satisfied.
It's OK if colleagues which I know well and with whom I have a kind of bond ask things like that. But not as a conversation starter or to create such a bond.
And the list of people who cannot stand questions like that goes on: those with depression for whom every weekend is just a period of grayness, those with social anxiety...
Inventing a story, rather than truthfully explaining that you "enjoyed spending time with your wife and daughters" sounds sick to me.
You have a bond with everyone else already: we are humans. There is no prerequisite.
As someone who identifies with both depression/anxiety and positivity toward my accomplishments, in addition to a definite introversion, I reiterate my last paragraph from above: stop lying to yourself and others. If you had a simple weekend, where is the shame in admitting it?
If it was bad enough that you can't admit it, use that to fuel your development instead of pacifying it.
It's OK if you don't want to spend the time to explain the nuance of your personal existence, but do understand that there is nuance in everyones existence. Expecting that the other person you are talking to "won't get it" is just blatant egotism.
Taking time to express what's important to you, and why, can be a very constructive thing for those who want to listen. The OP advocates empathy, and this is where it comes from. In my personal pursuit of empathy, I've had to filter out responses from people like you, and try to see beyond the untruthful statements in an attempt to understand what they are really saying. Shyness is one thing, but a pattern of lies and deceit are indicative of fundamental imbalance.
If you're having a hard time expressing why it's important to you, consider introspection; is it really important to you? If you don't come away from a day, or week, or weekend with something to tout when prompted, I dare say "you're doing it wrong".
I'm certainly not saying that I have something to be proud of every day, but that I'm honest with myself when I don't, and will express to others that I likely accomplished less than them in a given period. No lies necessary, and the other humans around you are given an opportunity to see your similarities, instead of some false iron gate of awesomeness.