Also, different bittering hops impart different KINDS of bitterness. You'll sometimes hear people say not to use a certain hop as a bittering hop because it leaves a harsh bitterness or recommend using a certain hop because it gives a very smooth bitterness. I've personally noticed very, very different characteristics in bitterness depending on what I use as the 60 minute hop. Also, although people say that bittering hops leave no flavor and aroma, that's not exactly true. The aroma is very very subtle and the flavor isn't necessarily going to be noticeable unless you only have a bittering hop addition (and even then, it depends on how much you use). "No flavor or aroma" is an exaggeration, but there isn't a lot of it.
If you look at different hop flavor profiles online, bittering hops and dual purpose hops will often have comments about what the characteristics of the bittering is. For example, Magnum is popular for its "clean bittering" character. I looked up Centennial and the same site said "Centennial is a much-celebrated hop in its versatility with its depth of bitterness and forward aroma — two characteristics that balance each other beautifully." And here is the same site's comment about Citra: "It has an extraordinary flavor profile of grapefruit, lime and tropical fruits but despite its high alphas, brewers often warn against its use for bittering, which is considered by some to be harsh and undesirable." I can definitely say that over the years I've come to narrow down the kinds of hops I like for bittering additions, and they are generally very popular hops for bittering whether they're extremely high in alpha acids such as Magnum with 14% AA or very low in alpha acids such as Hallertau Mittelfruh with 3.5%.