Why do some people tell loads of small bullshit lies and think you don't know?

[OhioOhioOhio]

I've noticed this a lot lately, particularly with regards to one person whom I'm kind of stuck with, for the moment anyway.

Why do they speak loads of unnecessary small lies? What gain do they get?

I don't say anything but I do quietly think 'fk off with your bullshit' each time.

When I was a teenager I worked with someone like this. You could be having a perfectly normal conversation and then she would say something that was so obviously bullshit. I would just think, why? She was a nice girl when she wasn't talking shit, so it must have been her own insecurities that made her feel she wouldn't be liked for herself, so had to make shit up to be more interesting/likeable. Or maybe she was just a massive liar and enjoyed people believing her rubbish. Just after I left that job I heard she had time off due to her nan passing away but it was found out to be a lie. I deleted her from Facebook when she claimed to be a tattoo apprentice and posted a drawing she had supposedly done. It was one of the top pictures when I searched Google

My mum used to do this. And she had a few lies she told about different people.

Eg when one of cousin's went to uni she had, "got her loan and spent it already" before she had actually enrolled at the uni.

It clearly wasn't true but when the next cousin went, he'd als, "got his loan and spent it already"

I'm not sure whether she actually believed it.

I went to school with someone who lied a lot.
She said she had a tonne of friends outside of school. One of them had a dad who worked as a camera man on kids TV and she could easily get us on a show. Somehow never happened.
To my embarrassment I believed this one, asked my mum for permission and was turned down flat. On the day she and all my other friends were supposed to be going I was very sad, but guess what? Due to a "mix up" it was all cancelled and didn't happen. This happened several times in different scenarios.
She had a Mysterious Older Boyfriend. Except she didn't. Looking back I have no idea how much of anything was true now, even the more mundane stuff. I am however, very certain that she didn't know Shane Ritchie and that she wasn't related to Declan Donnelly.
By A levels I had twigged that the majority of her stories were bullshit. If she really did have all these amazing friends and contacts then how come none of us ever got to meet even one of them? Ever?

I worked with a man who did this- constant lies that didn't hurt anyone but were just a bit pointless. I think his were mainly to make him seem more interesting and wise/lucky eg. he would always claim to have paid less than anyone else for the same thing (but strangely could never show anyone where to get the same deal/remember where he bought it), relayed fairly mundane stories with his as the hero (eg. I told him.....), often claimed to have been very close to or narrowly missed being at newsworthy events (eg was visiting a friend on the same street as a violent crime, should have been in London when the tube bombs went off etc).

On one occasion he sat right next to me and told a colleague a story of something very unusual that happened of his was to work- except it had happened on my way to work (and no where near his journey to work) and he had overheard me mention it to someone else.

I had a Saturday job in a shop as a teenager and the gangly teenager we worked with told us all he was taking the following weekend off because he was going on a modelling shoot in Milan. We saw him on a bus the following weekend and he pretended not to know us. When he came back to work he brazend it out and said he didn’t understand what we were talking about because he had been in Milan.