PSE vs GFE ?

Although I've been in the hobby for a while and have seen my share of providers, i still have trouble determining the difference between PSE and GFE. Some times when I request GFE it seems like its the same as PSE and vice versa. Perhaps I should see a provider that offers both and do a 4 hour session to get the correct explanation. Can anyone elaborate?
Well, from my perspective, based on having a sexy girlfriend recently, watching more hours of porn than I ever spent in achieving my two post BA degrees, lol and banging quite a number of hookers, I would have to say the two are defined as this:

GFE Girlfriend Experience means a ton of passion and a damn good fuck!
PSE Porn Star Experience means banging the freaking shit out of a good-looking ho! Gagging her with your Schlong, smacking her ass and piledriving her holes like your trying to bust up a street in the end. Lol oh, and let's not forget shooting your goo all over her face with the subtle aim for her eye. Lol

Any questions?

I prefer both depending in the mood.