late 10 minutes for work

I am use to go to our rental house every week,and Today is monday,it is time to go on working for the first day in a week.I got up as usual at 6:50 o'clock,and by a bus to Dafuyuan supermarket.when got there,i must transfer another bus no 312 to  my office.normally have this bus about 7:27,but today i had waited for 7:40 still have not seen this kind of bus,why ? i thougt i will late for work due to begin work at 8:00 everyday.From here to my office must take 25 minutes by bus,so i sent a message to my supervisor said i will be lated for a while this morning.

When i arrived my office,it is 8:10 now.my colleage and my supervisor both are in office now.and i felt she had some angry due to say big sound to me and always finded unreasonable trouble to me.i think to myself : i always do the work more than 8 hours everyday,but now i only lated 10 minutes.how unfair ! when i worked in a factory,when the office time is off,alway left office on time,no day did the work more than 8 hours.but now almost do more times everyday.

In the noon,after had lunch,i telephoned to my husband said this matter,and he said to me don't be narrowness.ok,I think so.