Too Many Credit Cards?

Is there such a thing? Can it be bad for your credit score? I got Tangerine, Simplii, BMO, RBC, PC... Switched to Rogers for phone recently and now I am considering getting their credit card for enhanced cashback redemption plus 3 percent cashback on USD.

But is having 6-7 cards ridiculous? Should I close down some of them or is there no downside? I never use the RBC or PC ones. I'm not paying annual fees for any of these.

I don't have credit card debt or anything like that.