Purchasing the iPhone 5s

What consumed (kind of) my life for the past few days was over in a matter of minutes, or so I thought.
I had a problem, or rather, a new "want". There was no real need, but since I was about to get anyway, why not get it?

So here's the context: My current xiaomi is not getting any data speeds higher than 2G + it's battery life is declining (or so I think).

So I decided, why not just get a new phone and then stick to it. And if I want to get a new phone, let's get a good one, one that would last me 2 years at least.
And so I went about looking for iPhone 5 / 5S.

I thought, how about a second hand phone? As in, it won't be so crappy, and it would still last, because Apple right?

So I looked through Amazon, and then Germaine/Sean showed me this website which acts as a "flea market".

And I bought a second hand iPhone 5S for $450, and to think that I was happier?

Yes I was happy, but several considerations soon popped out:

1. Why was I so weak, and flinching? Should I have said no? The phone wasn't exactly in mint condition, and the front screen has some minor scratches
2. Should I have tried to negotiate more?
3. Shucks, now there are some things that Android has that iOS doesn't (think of widgets in home screen)
4. Should I have just spent the extra $150 (that's about 33% more) and bought a new fresh phone from Apple store?
5. Should I have risked and took a gamble and bought the iPhone 5S from Amazon which claimed to be in better condition and provided even the earphones - all for the same price?
6. Do I even need to get the phone in the first place?
7. Why not just get iPhone 5 instead of 5S? Do I really need that?

All the more I tried to pacify myself and fight the cognitive dissonance, the more I realised how contradictory I have become. Have I become so materialistic? Am I really someone who wants to always "win", as in trying to get the best of both worlds? 
Ugh... I have to stop and just accept my decisions.
I have made so many decisions, which only after "experiencing" it, then I realise my decisions were wrong. And thing is, I could have thought of it....

Ugh...