Again, I am referring to an environment where guys wear suits and ties all over the place. Also, do you look at the ties as an object alone or do you look at how it is going with the rest of the attire? Do you care about how well it is worn (i.e. the knot)?
For me, when a guys wearing a suit, it's one of the most important components if he's wearing one. The suit can be immaculate, perfectly tailored and pressed, nice material etc - but if it's paired with a bad tie, or a tie which doesn't match, or one which has too big of a knot or too small of one, or a crooked one, or whatever - it can really ruin the overall appearance.
I mean, the devils in the detail; why go to all the effort to make yourself look good with a nice suit and shirt and shoes etc - and ruin it with a bad job with the tie? It just look unprofessional and scruffy.
I will first look at the attire and then the tie, lastly the knot.
A guy can wear the perfect suit, but all will be ruined by a tie that doesn't match in color, design, etc. Also, a crooked tie and/or the size of the knot which is too big or too small will affect the overall apperance.
Also, it also does matter (to me, at least) if the belt and shoes worn by the guy are of different colors. Somehow, these 2 items are quite commonly missed out. One project manager in my team has this habit of wearing brown belt with black shoes (with shirt & pants) till I told him about it. It just doesn't look right.
Suits are quite simple, doesn't have much difference. So that make it more obvious : whether the tailoring fit you very well, what material it is, do the the tie, belt and shirt match with your suit... Office time is too boring. Its fun to notice the details.