I have a late 2013 13" rMBP. The last few weeks I've been having issues with my wi-fi. Sometimes it works great and other times I can't get pages to load. My wife's MBA works sitting right next to me, my iPhone works fine. Could there be a problem with my MBP, or just an issue with getting a good signal. Is the router overloaded? I turn the wifi off and on, sometimes it helps, sometimes it doesn't... Any advice? For example, I was able to open this page but then went to submit my post and it didn't work. I had to close Firefox and restart, and turn off wifi to get it to post.