This is one reason why I will never take money from an external investor. There are some scenarios when you definitely need an investor's help. But right now, the trend is almost like "it's a cool factor to seek investment for your startup".
The problem with taking money from someone else is that, you become obligated/answerable to them. Remember, we all start-up because we don't want to go down the traditional working-for-a-corporate route, because we don't want to be answerable/obey no one/their orders. But seeking investment (in most cases) just defeats this purpose of starting up.
Why the hell would someone want to be answerable to a third party for running YOUR company in YOUR way?? And what happens when that company fails? You need to either apologize/console the investor that you will somehow get back his money. Contrast this with having no investors at all, worst case scenario would be you lost all your money. But that's much better than losing someone else's.
I find nothing wrong in trying to build an Saas that generates $10000-$50000 a month in revenue from day one, without external investment, instead of seeking millions in investment for a bunch of photo filters on a phone only to later worry about monetizing the idea.