Excuses are nothing more than distractions keeping you from being successful. Whether from a co-worker on a team or yourself, they are unacceptable. Keep a focused mindset and accomplish your goal.
Five quick things to remember to stay on track:
1. Have a ‘don’t care’ attitude when it comes to excuses because all it means is the work did not get done.
2. Be able to identify when you don’t meet the expectation.
3. Adjust and plan to determine if the goal is still a priority. If it is, create a new plan or amend the current plan to hit your target.
4. Take responsibility.
5. Only you decide your level of success.
TwoGirlsConsulting LLC (2GC) 
I agree with these ways of thinking because the only person left to blame in the end, is yourself!