You'll have some growing pains to go through. 

Cash: Cash may seem great, it's real and doesn't bounce, however, it usually means you have to meet your renter in person to collect which can be a pain and it's hard to keep track of.

@Sergio Rodriguez, I feel your pain, finding deals is a complicated, time consuming process.  

Cold call as an unrelated investor and create spreadsheets detailing each leads pain points and motivation level.

You definitely feel my pain then.

@Kevin RzeszutoI feel your pain. 

So those are other problems/questions to be answered.These are all growing pains.

For me, my pain points were marketing, screening and collecting rent.

There are plenty of people much more successful than myself who have never gotten a license. sometimes its more of a pain jumping through hoops than it's worth.However, if you want to make a career out of being an agent, you'll obviously have to get it.

Want some examples: the first thing you will notice is wreckless and agressive driving (even by my standards), people running red lights at full speed long after the signal changed etc - what you don't whitness very often because it happens so fast: items stolen out of cars, cars stolen, tools stolen, materials from jobsites stolen, copper pipes cut out of basments, people following the UPS van to pick up amazon packages and selling content on craigslist, someone in serious withdrawal pain may ask you for $5 gas money and then ask for your wallet and cell phone while flashing a gun, domestic violence, people yelling on the street, shots fired at night etc.