Question: Why does it feel wrong to tell my friends no?? 

Answer: Its because they are your friends and you want them to be happy.  Just make sure that you aren't getting pressured into doing things that are dangerous or that you really just don't want to do.  In that case, they are the ones who should be feeling guilty and maybe arn't such great friends after all.
This question from the Yahoo Q&A forum is categorized in the topic: Sports