Gen advice + handling technicals you don't know

ballhard223, honestly, there is no best way to handle not knowing the answer to a technical question other than saying "I am sorry, I do not know the answer." The thing is, in 99% of situations, not answering a technical correctly is an automatic ding. This goes back to why technicals are asked in the first place: to eliminate candidates. There are thousands of applicants for only a handful of positions, so IBs have to find ways to cut that number down, and asking technicals is a very easy way to do so. If you miss a technical, you gave the interviewer what he/she wanted: someone to eliminate.

If you become flustered during an interview (I assume you mean that you were visibly annoyed), you will 100% of the time get dinged. What you did was tell the interviewer that you cannot handle long hours, complicated requests from clients, demanding senior bankers, etc. The interviewer is probably thinking, "Wow, if this guy got so mad at me, imagine how mad he will get when our MD asks him on Friday to finish a pitch by Monday or if our client questions his DCF."

Now, for the advice....first, there is no excuse for missing a technical question. I know that someone is going to come here with their story about how one time a friend of a friend missed a technical and still got the offer, but that almost never happens...as in 99.9% of the time it never happens. With all the interview guides available to you, there is never an excuse for missing a technical question...never. That being said, you have already accomplished the first order of business: understanding why you got dinged (you were unprepared and acted unprofessionally). The first part is easy to solve: study your technicals more. But, this time, try to understand the concepts behind the technicals- don't just memorize formulas and answers. Second, take a deep breadth and pause before answering a question in an interview. The interviewer isn't grilling you because he/she doesn't like you- it's not personal. If you get mad during an interview, you will get dinged every time. It's just not professional, especially since you will get reamed on a weekly basis by your bankers and by clients. It's part of working in professional services, especially when you're the lowest guy on the totem pole.

I would start emailing boutiques, like you alluded to doing, and see if they need any interns. I did a CapIQ search a few months ago, and there are over 300 in NYC alone, so you certainly have plenty of opportunity. I hope that all helps. Good luck.