Not scummy, but not recommended either.

There are plenty of fish in the sea. Why waste your youth on waiting for one girl?

Keep her friendzoned and in contact with her while you find other (better, single) girls.

It is a disaster to "wait" for a girl in a relationship. It will become extremely frustrating, and it is a terrible way to live -- you are always unsatisfied.

I've had girls I've had my eyes on for YEARS and they are still with mediocre guys. Girls have many reasons for dating the people that they do. Sometimes the "issues" and "mediocrity" is actually what the girl is looking for. I've been friends with girls who were in completely doomed relationships, but they stuck it out for months.

"Stealing" is not a very good strategy unless she seems receptive. Most of the time, it will activate the slut alarm in them and they will resist. It also sucks for the girl if she liked you as a friend. You always want it to be a GOOD thing when you ask a girl out. That's hard to pull off when she's with another guy and when she wants to be friends with you.

Most people seem "unhappy" in their romantic relationships, but it is usually what they want. What you see is not what she sees.
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San Francisco Giants 3x World Series Champions (2010, 2012, 2014)
Golden State Warriors Reigning Champions (2015, 2017, 2018)

Is waiting for a girl to go single a worthwhile plan?

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