Believe lies

Is lie = joke?
I realised human always explain their behavior as joking when they are actually lying.
Joke is something that make people happy or feel fun by telling a story.
Lie is something that make you feel fun by fooling your friends.
See the difference?
Everyone will have fun when you tell a joke, but only you will have fun when you tell a lie.
Okay maybe your friend will also laugh when they know they are cheated, but the reason that make them laugh will include embarrassment also.
Well, i have this friend, below is our conversation:
HE: you need to know me more then , i'm only serious on rare occasion
ME: then you also need to know me more then, i'm only not serious on rare occasion
HE: my my , you live a tough life then
ME: you live a crazy life then
What i wanna say from this conversation is that,
is people like me will have a boring life of being serious?
Well, i dun think so....
Next:
ME: what a petty boy..
HE: what a stupid girl
HE: believe everything i say ..
Okay, please dun misunderstand anything, we were talking about when is his birthday and that's how this conversation come out. He was trying to make me believe that his birthday is on 15th on February when he wanted to celebrate his birthday on 11th of January. Indeed his birthday is on 15th of January.
Actually i did suspect his birthday is on January because normally people won't bring forward their birthday celebration for a month. But after his crap explanation, i noob, idiot, stupid go and believe him...
Well, you know what. I always believe people no matter what they say.
I dunno why people must lie?
My dumb record is 3 times! My cousin use the same lie to cheat me and make me believe him for 3 times, xianzzz...
I'm not stupid or innocent, just that i did not expect people will lie upon an unnecessary thing.
So i will just believe, i always expect what i heard is true.
But human will always learn from experience, i learn to cheat my friends also:)
However, i think believe people is a bad habit:(
Even though i feel my friends maybe cheating me, i will still choose to believe he/she.
Unless got a person down there tell me that my friend is lying, i will then dun believe.
Because i choose to believe the person who tell me my friend is lying!!
Hmmm....sounds confusing...
Never mind, so what is life?
With these lie in our life, what is life for?
Can't human don't lie and tell truth?
I believe very hard....LOLX