I have found the biggest culprits are the social widgets and fancy js library. Ads and analytics rarely slows down a site (for me). There are exception though l

I have found the biggest culprits are the social widgets and fancy js library. Ads and analytics rarely slows down a site (for me). There are exception though like few days ago I bumper in to a site that had 6 different analytics. That's just crazy, also outside widgets can load their own analytics (I think disqus does that). Things can quickly turn dirty.