What is a creative excuse to give your boss when you are 30 minute late coming to work in the morning?

I ordered coffee for you and forgot to pick up so I had to go back to coffee shop.

Attending to an shareholder's/investor's call

I am sorry but I am the mother of 3 children!!!

haha its a funny but a really intresting question if i will be the employeei will absolutely use that santence that my transportation source is late so i came late so please sir i msorry for that inshaALLAH I WILL BE NEVERCAMWE LATE AGAIN.

sorry sir i oversleep becuse last night i don't because i was searching for a solution for the issue we faced

or

heavy traffic

or 

i oversleep i could came at time but had a breakfast to be with my full focus in work.

Regardless of the bus transportation strike, and my 30 minutes late arriavl, I was able to start working and producing when I was on the train :)

I actually came early by GMT

Sorry Sir/Ma'am but my phone suddenly went in to daylight saving mode because I forgot to update my iOS software and it had a technical glitch. Due to that my alarm went off later, hence I am 30 minutes late to work.

Was occupied on an unavoidable official call . Though am never late.

I was engaged with an official project which delayed my morning schedules.

i said that on way i have meet an old lady which need help from me to reach her their residence so i never come late again