So, i have had my first ever rMBP for about 3 weeks now. Coming from a PC, i love my new mac. I love that i don't have to worry about a virus by downloading third party apps or softwares. My question is, is it safe to install adobe flash player? will it make my macbook slow and hotter? edit: the reason i am asking this is i wanted to watch youtube videos. However; youtube videos require adobe flash player. Any alternative from the Appstore that can play youtube videos?