One can never prepare for an interview is the only feeling I get after every interview I face. This too was the same. The TL was extremely smart to point out your negatives. The discussion went from 'why should I hire you?' to almost everywhere, about my daily life, activities. One can simply not plan up answers. Extremely good communication is a must. Being quick witted, upfront, smart and having a smile on the face helps. And yes, asking relevant questions give a good impression and implies that one is really serious and has given a thought about it. Simply for the sake of asking can be easily caught.