So, an overleveraged property that had no equity to begin with and now an additonal loss from the costs of selling.What could go wrong?

Hello Bigger Pockets, I am hoping someone can help me figure out what I am doing wrong using the BRRR Calculator. 

Drive slow up/down the wrong street looking like you aren't from there could get the cops called on your or worse.

If lots goes wrong, the rapid appreciation and hot market provides a good exit strategy.

Since I have done both of these things wrong and right in my past, I can tell you keeping the client happy to a certain extent is a lot more cheaperWe have found that setting the proper expectations right up front of what we will and will not do seems to help solve going down this never ending rabbit trail sometimes.

If you do it wrong, it's just wasted admin costs. 

I may be wrong and my CFP's may be right but I am thinking...Is it better to (1) leave the money in 401k and let it keep ballooning and invest in RE with pre-tax money? 

Even if you aim wrong, it still works.

I can imagine that, with the wrong mindset, it could feel like an invasion or disrespect of your personal space. 

This is standard business practice - just look up how many settlements the SEC makes annually where companies pay millions in penalties WITHOUT ADMITTING to any wrong doing.- Cash-for-Keys is another example of this!