If saying yes means showing up late and disheveled, being physically present but mentally elsewhere, or being anything but your best self, say no.
It is better to disappoint someone by saying you won’t be able to do it justice than to give 50%. Half measures don’t help anyone.
Saying no also means you care – about your effect on people’s energy and happines, about making sure you don’t get in the way of the success of the project you are saying no to, and about everyone else who is actually looking forward to having a great evening.
When you’re in, be in.
PS: Don’t say yes when you want to say no.
A Learning a Day 