Humans are, by and large, not very creative when they are older. The freewheeling creativity of our childhood is deadened by a fierce mix of academic indoctrination and modern desk job monotony.
So, when you give the players of a tabletop RPG a list, they're immediate unconscious reaction is this:
The list is all there is. Everything that exists is on the list, nothing that exists is not on the list.
So if you show your players a list of skills they can choose from, then they won't create a character that specializes in something that isn't on that list.
The first time I played the amazing game called Risus, my players took a good hour to make their characters. Making a Risus character is about a five minute process, even if you have just encountered the rules for the first time. But my players sat and pondered their cliches forever, because they couldn't stretch their mind around the blank space. They were afraid that this or that choice might screw them over in combat, or overlap too much with other party members. And they were especially afraid of just throwing out an idea.
But the more you play Risus, or other fast and loose RPGs, the more comfortable you become with doing weird and awesome things, and defining your character more by what they've done and less by what mechanics they are made up of.
For example, in 13th Age, characters don't have skills, they have backgrounds, and much like a Risus cliche, a background can be anything. We're not talking "Acrobatics +4," or "Use Rope +6," we're talking "Famous Spinal Surgeon +5" and "Ex-thrall of a Mindflayer Overlord +2."
I like this. I dislike how high their numbers go, but I like the idea. 5e D&D did backgrounds (as an optional feature) and at first I was really excited, but as it ends up, 5e backgrounds are just another way of quantifying abilities and sneaking in skill training. It allows you to invent any new background that you want (awesome!) but it shoe-horns you into a set format of Skill Proficiencies, Languages, Equipment, and Features (boo!).
I say, let the players go wild and describe their backgrounds however they like. Give them a couple mathematical bonuses to distribute among these backgrounds so it doesn't break the system (I like +3, +2, and +1). Adding a quick rule about how they can apply these bonuses (i.e. only ability checks, not attack rolls, etc.) ties it up nicely.
This is dangerous idea, however, when over applied. Weapon lists can be seen this way, but most people aren't as knowledgeable about weapons as they are about different backgrounds a character can have. If you don't describe the benefits a whip conveys when a character wields it, players are not likely to think of it as an option.
Classes are the same. Do warlocks exist in your world? How about rangers? This kind of blank space isn't easily filled by a player's creativity. If you don't give players anything to go on, they will flounder around, or even wore, stick to the stereotypes.
Look through your game and ask yourself if the lists you are handing to your players are helping them be creative, or boxing their creativity in.