The question opens up a huge can of worms which you can dig deep and explore further. Between, megalomania, shyness, a total lack of enthusiasm or someone with a temper problem.
b) Tell me about the biggest and hardest project that you've worked with
How detailed the person gets and the kind of topic he covers will let you know whether he's
- A people person
Talks about the stakeholders, the team, the challenges with the customers
- A techie
Jumps right into the how many components the solution has, but before he/she can move to the next component, you've already got a huge gobbledygook of why the 64bit processor driver couldn't work with the HBA drivers.
- A faker
Everything stops at level 1, you just can't prob him any deeper.
- A liar or someone who just forgets easily
"I've never been in any difficult situations". Potentially a good/dangerous sales person
- Highly committed but sarcastically jaded and cynical
May be a whiner, or someone that will put in a lot of effort. Be wary of whiners as they tend to give 1001 excuses why something can't be done.
- A quiter
The problem was never solved, but he's resigned, or decided that it's too dangerous to proceed
- A good guy
Probably doesn't exist, unless the company went bust.