(How Perfect is Too Perfect?)
Character flaws are an integral part of making your character likeable to your readers. Believe me when I say, the more perfect your character is, the more your readers are going to be turned off by him or her and the more likely they will be to drop the book and never read it or another one by you again.
The reason is they won't be able to identify with the character. No one in this world is perfect. If you make a perfect character, your readers are going to feel inferior to that character and hate him/her. They're not going to like the fact that s/he is always right, always wins, always knows everything, always says the right thing, etc., etc.
You need your character to get in arguments, to be wrong in arguments and to, ultimately, admit that they were wrong and to apologize, thus having a growing experience.
This doesn't mean they have to be wrong in every single argument. But have a big argument, possibly a moral one, and have your main character be completely wrong. Then, have something happen that proves the truth to your character so that they go back and admit that they were wrong.
Also, if you're doing a series with this character, that's all the better. Not simply because people will excitedly buy the next books, but also because it gives your character more opportunities to grow. The more flaws you give them, the more chances you have throughout the series, to bring the character to his/her final maturity.
Don't have an idea of what you can use as character flaws (also called weaknesses in the Character Sheet)? Here is a list to get you started:
1. Pessismistic (the belief that the worst thing is going to happen in every situation)
2. Cynical (distrusting the motives of everyone and everything)
3. Sarcastic (always mocking the comments people make)
4. Feeling Pride (the opinion that oneself is better than someone/everyone else)
5. Showing Pride (the act of verbally/physically expressing one's pride/arrogance)
6. Blind Stubborness (unreasonably inflexible, not giving in when it is obvious to everyone else a better alternative can be reached later)
7. Selfish (hoarding things to oneself)
8. Dishonest (tending to lie a lot about everything)
9. Need to Be Right 24/7
10. Playing the Victim
11. Control Freak (needing to always be in control of everything)
12. Greed (wanting everything and then some for yourself)
16. Fear of Something (heights, spiders, death, etc.) to the point where it can get others hurt or even killed
18. Concern only for oneself
19. Indecisive (inability to make decisions)
20. Slow-thinking (inability to come up with/respond to something immediately)
21. Disability in one form or another (mental/physical i.e. needing to wear glasses)
22. Inability to Adapt to situations
23. Folds under pressure
24. Angry (quick to anger/angry all the time)
25. Cold hearted
26. Refusal to let go of things, even when there have been apologies (i.e. let go of past quarrels/wrongs made against him/her, etc.)
27. Desire for the Unrealistic (i.e. wanting something they can never have/fantasizing about having something they never can like the way 'things used to be' in some odd time or another or a certain person, etc.)
28. Inability to move on (dwelling on things)
There are more character flaws than these, of course. These are just to get you started.
A character should always have at least two flaws. Especially a main character. This way, your reader can watch them grow and grow with them.