Well, it all deends on how much you like something.
We are buying for the first time and I found a house very quickly that ticked most of the boxes - having thought about what the boxes were for a very long time. I made a list and it passed almost every single point, and also I thought my family would like it - which was a big deal as we're buying it together.
I think of it a bit like finding a husband, which I have never managed actually - but same sort of principles. Think of the important stuff, is it big enough, is it rainy day proof (ie enough space indoors not to feel compelled to go out all the time) and sunny day proof (ie enough space outside for you to enjoy a nice day - especially if you have a few children)?
Is it in a nice, safe, quiet street? Are you likely to fit in with the demographic? Is the house itself sound enough, only requiring work you can afford to have done or enjoy doing yourself?
And finally - but most importantly perhaps - do you actually love the feel of it? Because if you don't, you'll not like being there.
I saw a beautiful place round the corner from it, before, and it had just gone - it was untouched since about the 1930s and absolutely gorgeous, but it had been sold. I was gutted but it made me notice that part of town and then I looked for something nearby and found the one we just exchanged on.
Sometimes the things you aren't certain about, are actually not that important after all. I know it's the right house, because we pulled out of the purchase after it had taken 7 months already and a couple of weeks later I woke in the night and realised I could not BEAR the thought of someone else having it, or even looking round what was by then OUR house.
So we prostrated ourselves on the Estate Agents' floor and begged to have it back, for an extra 5 grand. And they said Ok. I could have danced round the room. 
Only problem is I keep thinking now I've got it, something else will go wrong, as it's too good a thing to happen to me. Arghhhh!