I have an ENFJ friend, and we were friends in grade school and basically have remained loose childhood friends ever since, but now that we're going to the same college I see what an emotional wreck she is right now. I think ENFJs are awesome, but my friend is really beating herself up right now and pushing herself too hard. She says she worked a forty-hour week waitressing and she's in college! In fact, we have two classes together, but she's missed the last two days of both.

Unfortunately, I really don't know what to say to her to help her, but she has me if she needs me. I find that when people are highly critical of themselves, they're also highly critical of others, and this is the case with my ENFJ. I know she's a sweetheart but she's so stressed out right now that we're not very close.
I wish she'd REALIZE how amazingly wonderful she is.
As for INFPs and ESTPs, I think my older bro is an ESTP. He's hilarious, good-looking, has probably had a million girlfriends and gone to a million parties, drunk a million beers, pigged out in hundreds of people's fridges, and just lived a very on-the-go and exciting lifestyle. He's in the military now, but he visited last weekend and we had the most hilariously fun time shopping for movies in the movie store. He began quoting Borat at me, and I laughed and laughed. I really couldn't stop. His smile is just the funniest thing. I love his sense of humor sometimes, and he has the most amazing memory. I mean, he was quoting Borat word for word.

Dom Se's, LOL.
One thing I will say though, is that my bro can be surprisingly easily offended and nasty sometimes. I don't know what triggers it, but I've never been treated worse than by him when he's being nasty.
We've had our fights in the past, but I think my brother is overall a really funny and interesting guy. Forceful, but fun. If an INFP and ESTP both like and love each other and commit themselves to work on the relationship together, it can definitely work, just like any relationship between two loving, committed individuals can work. I think my bro is also an E7, and I think that really influences his behavior, so I'd take into account a person's enneagram type as well when trying to understand them.