I'd be immediately suspicious of any salesperson who tells me that a bike is perfect for me. I'll be the judge of that, thankyouverymuch.

The two LBSs where I went bike shopping put me on about 12 bikes total between the two stores. Worked with a really good salesguy at each store, and with every bike he did a quick basic adjustment and would ask me how it felt, have me take a loop around the block, ask me again what I thought about it. Both guys just provided information, answered my questions about the different specs, and did really good questioning to get me to think about the bikes like "how would you compare bike A to bike B, and after trying C now how do you feel about A or B" to comparatively rate each bicycle. Neither guy ever tried to impose their impressions of anything on me. In the end, I feel like I got the best bike for me. The only person to tell me it was "perfect for me" was the professional bike fitter who adjusted my ergonomics after I already bought it.

When I started bike shopping I was really overwhelmed with all of the possible bikes, sizes, frame materials, prices, etc. What really worked was to just try a lot of bikes. After about 5 hours of test riding, I knew exactly which bike was perfect for me.