Emotional 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.
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. If you have a series, I would choose 5 flaws so once your character defeats one flaw, they can start working on the next, just like in real life. Choose one flaw to be the major one, while the others are subtle and go unnoticed until the first flaw is fixed, then the next one can show itself boldly. Remember, also, a person—even once they have worked on a flaw—will sometimes fall back into the flaw from time-to-time.
Look at your friendships and relationships with those around you. Use your and your peers’ flaws.
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. I.E. "We're all going to die")
2. Cynical (distrusting the motives of everyone and everything around them, cynics are often confrontational. )
3. Sarcastic (always mocking the comments people make)
4. Inner Pride (the opinion that oneself is better than someone/everyone else, feels it but won’t necessarily expose their pride)
5. Showing Pride (the act of verbally/physically expressing one's pride/arrogance to others)
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, also the lack of caring of how others feel)
8. Dishonest (a compulsive liar)
9. Need to Be Right 24/7
10. Playing the Victim (someone who twists situations around to make it look as though they were the ones who were suffering)
11. Control Freak (Everyone knows someone like this)
12. Greed (wanting everything and then some for yourself, a sub-category of selfishness)
15. Cowardice (we’re not talking the normal fear that everyone feels in desperate times with that fight/flight instinct. We’re talking bold outright cowardice; someone who does everything they can to stay out of a sticky situation and make sure others reap the hazards. They’re only goal is to look out for number 1. Also people who put the blame others just so they themselves won’t get in trouble for something they did, but especially when that other person had no part in a situation.)
16. Fear of Something (heights, spiders, death, etc.) to the point where it can get others hurt or even killed
18. Indecisive (inability to make decisions)
20. Inability to Adapt (will oftentimes be stumped as to what they should do when things change all of a sudden because they can’t cope with changing situations)
21. Folds under pressure (characters often have high anxiety)
22. Angry (quick to anger/angry all the time)
24. Holds Grudges (i.e. refusal to let go of past quarrels/wrongs made against him/her, etc. and refusing to accept apologies)
25. Lives in Fantasies rather than Reality (i.e. wanting something they can never have/fantasizing about having something they never can like the way 'things used to be', or about a certain person, etc.)
26. Inability to move on (dwelling on things that happened in the past, rendering them incapable of moving forward)
27. Workaholic (taking on so much work they oftentimes overwhelm themselves and their daily lives are often filled with stress, especially from not being able to finish all the work they set out to do.)
28. Immature to a fault (especially when they’re old enough to know better than to act a certain way)
29. Torturer (these characters love making others suffer, generally for no other reason than to see others in pain. They may only purposefully say hurtful things, or go as far as physically harming others)
30. Quarrelsome (always fighting/arguing about something)
31. Town drunk
32. Immortal Complex (These people tend to think nothing bad will ever happen to them and may fall into a state of shock when it eventually does. They will often endanger their own lives or others’ lives because of their unrealistically high optimism.)
There are more character flaws than these, of course. These are just to get you started.