Boat buying = marriage
Most think they know what is "best" for them. Some actually seek counseling before taking the plunge. Some go for the skanky trash that need alot of cosmetic work but are cheap and easy to "get in." Some go for the high faluting biotches with very refined tastes but are also "high maintenance."
Some have been 'round the block before and either make the same poor decisions (masochistic) or have learned what its really about and have matured and make a decision based on what fits them the most.
However, either way, most people will have it in their heart to make a decision based on just that.
I'll bet the guy the OP tried to talk out of buying "his" boat will buy one just like it.