Replying to Having three credit cards. Can it affect my credit score?

I have excellent credit and i treat my current two credit cards as if they were debit cards (charge something on my credit card, and then pay it off instantly). I've never paid any interest due to the fact that I never let my balance roll over into the next month. Chase has a new offer that gives you a $200 bonus if you spend $500 in the first three months. Looking to sign up simply to get the bonus. So my question is, is it bad to have a bunch of different credit lines open? Does having multiple cards affect your credit score in any way? Like I said, I always pay my balance in full, just wondering if simply having a bunch of credit cards can affect your score negatively.