Are you wheat? or tare?

Something has always seemed a little off to me about the parable of the Wheat and the Tares. Until I had an insight this week. The parable goes...

• The kingdom of heaven is likened unto a man which sowed good seed in his field:
• 25 But while men slept, his enemy came and sowed tares among the wheat, and went his way.
• 26 But when the blade was sprung up, and brought forth fruit, then appeared the tares also.
• 27 So the servants of the householder came and said unto him, Sir, didst not thou sow good seed in thy field? from whence then hath it tares?
• 28 He said unto them, An enemy hath done this. The servants said unto him, Wilt thou then that we go and gather them up?
• 29 But he said, Nay; lest while ye gather up the tares, ye root up also the wheat with them.
• 30 Let both grow together until the harvest: and in the time of harvest I will say to the reapers, Gather ye together first the tares, and bind them in bundles to burn them: but gather the wheat into my barn.
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• I mean, I understood the idea that if you pull of Tares that you will also pull up Wheat because of how the roots intertwine in the soil, but I never really understood the practical application of this. I mean life is hard enough without having a bunch of tares in it. 
• But then I thought, how and who would decide who is  tare, and who is wheat. The only reasonable answer would be that God must judge, but then why did God through Christ say to let them grow up together? I understand the farming complications, but I've never really thought it would be all that hard for God to do something about the bad people.
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• As I was thinking about this, I remembered that you can't tell the difference between Wheat and Tares until harvest time. So it follows logically that God will not judge the difference until the end of our lives. Certainly we can do both good and bad things now, but I suppose to God, we really aren't all that different from each other, and it won't be until the final judgement that we are judged whether we are wheat or whether we are tares. The good news is that we can choose.