I want to know if i am not the one, any of you loose a client for delaying in programming and do not finish in the date you promise to finish

Or anyone of you loose a job or client because you do not know enoguth of certain task to do and can not do it?

For example to install my vb.net application in a operative system windows server 2008 i had to install sql server agian with other additional software, i hoped to finish it in one day but it takes me about 5 days to accomplished it.

How do you lift your spirit?

Thank you in advance for the answer

Luis