I got some good advice in one of my lectures today from the co-founder of my film school (Stephen Kopels gets the nod on this clever colloquilism). The worst thing you can do is preface a presentation with an apology. That works with everything in life. The key is to do your best and then present it confidently as being your best. If your presenting something (be it powerpoint, painting, film, code, project, or absolutely anything) do you want the audience to walk in with a negative mood or a positive mood? The example Stephen used was cooking someone dinner. If you goto someone’s house for dinner and the cook starts the meal with apologizing for overcooking the chicken, you are going to look for flaws in the food instead of enjoy the dinner. So don’t apologize for your chicken, whatever your chicken may be.