Top 10 Snafus to avoid when building a good rig

Falling for the first pretty faceplate that comes along.

0)Not having a clue what you really want from a rig.
1)Basing purchases on reviews.
2)Asking in forums which one is best for you.
3)buying something because in theory it has to be the right one.(or type)
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4)Handing big money to a complete stranger at a show who promises to build you a product "as soon as he has a chance"...
5)handing money to a complete stranger who promises to revamp you average item into a worldclass product
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6)buying a turntable missing ANYTHING.
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7)not taking ANY claim with a large grain of salt.
8)believing any of this stuff other folks post without analizing it and understanding it.
9)not knowing yourself

Convincing yourself that a particular component is going to be the holy grail, thus justifying spending more money on it than it is really worth or can be resold at.

Judging deficiencies in your system before new components/cables are fully broken in.

How about plopping down a new pair of speakers and then doing everything possible to make them sound better, including buying all kinds of different electronics, ICS, etc., but forgetting to tweak the placement and get things tuned in first.