Having a frustrating fantasy football draft is never a fun feeling. It starts your season off on the wrong foot, and it ruins the fun of the game.

One way to delay destruction is to be prepared for your draft, and that starts with knowing the settings of your particular league. Our fully customizable draft kit and draft kit app help with that.

But you also can get burned if you're not familiar with your site's draft lobby. Doing mock drafts on a site such as FantasyFootballCalculator will help you figure out who you like, but it won't necessarily prepare you for a draft on NFL.com.

Realizing that players are ranked drastically differently than what you expected is a tough thing to adapt to in the middle of your draft. So practice up on your particular site, whether it's ESPN, Yahoo, or NFL.com.

Oh, and just keep reading to see which players are overvalued or undervalued in NFL's default drafts, according to our draft kit when we tailor it to NFL.com's default formats.

Fundamental Principles

1. The flex position is only for running backs and receivers. That means just 12 tight ends will be in play in a given week (or however many tight ends are in your league).

2. But there is still a flex, and that means running back scarcity is a real thing. On Yahoo, you can roster only two running backs in default setups. On NFL.com, you can roster three, and in standard leagues, you generally should -- if you can land three bell cow backs. That doesn't mean to load up blindly on running backs compared to receivers, but it does mean that primary backs have a lot of value in this format, as you'll see when we break down our algorithm's expectations.

3. Wide receivers are overvalued. If you're playing in a standard setup, wideouts are overvalued. If you're in a PPR league, that's different, but the default league is standard scoring, and that means wide receivers are listed too high, according to our algorithms.

4. So are tight ends. Remember, you can play only one tight end, and that means streaming is a smart way to go in default leagues.

5. There are six bench spots. So you especially don't want to roster a second tight end with a short bench.

Overvalued NFL.com Players According to Our Projections

Inside NFL.com's top 100, there are a whopping 24 dudes our algorithms identified as players pegged at least 16 slots (a round and a half in 12-team leagues) too soon.

Surprisingly, none are quarterbacks -- all of whom are pretty much undervalued by this method.

But our algorithms think NFL.com's lobby lists three veteran rushers (Adrian Peterson, LeGarrette Blount, and Marshawn Lynch) at least 18 picks too early. There is also a trio of young backs who are even bigger mis-prices, per our algorithms: Samaje Perine, Kareem Hunt, and Derrick Henry.

Some big-name tight ends also find their way on this list, primarily because of the league setup. Unless your league mates are weird, there should only be as many tight ends rostered as there are teams at any given time. That will leave about half of the league with surefire studs (Rob Gronkowski, Travis Kelce, Greg Olsen, Jordan Reed, Jimmy Graham, and maybe one or two others depending on your definition). That will reduce competition for picking up hot options from the waiver wire.

The rest of the guys on this list are all wide receivers. That stems from the fact that running backs with guaranteed workloads are more valuable than secondary -- or in some cases, primary -- wide receivers, based on these league settings.

This doesn't mean you can ignore wideouts, of course, as loading up on running backs leaves you vulnerable to injuries, but the default format values running backs here. Picking the guys who carve out roles and stay healthy is a different story, so don't get overconfident.

Undervalued NFL.com Players According to Our Projections

By contrast, there are 15 non-quarterbacks inside our top 100 who are listed at least 12 picks (a full round) later than our algorithms think they should be in the draft app on NFL.com.

It's not unreasonable that a guy such as Terrance West could be found higher on NFL.com's list as we get closer to the season, but their lobby is also a bit more hesitant on running backs in potential timeshares or who aren't full-fledged workhorses (Ameer Abdullah, Spencer Ware, Latavius Murray, Mark Ingram, and Rob Kelley) because of their inherent devaluation of rushers.

Again, if you're in a PPR league, make sure you adjust our draft kit, so you're drafting optimally, but if you're in a standard setup, you can target some running backs at a value price, according to our projections.

Hidden Gems

Austin Seferian-Jenkins should go undrafted for a lot of reasons in this format: he's suspended two games and you can play just one tight end, but there's a chance he's the New York Jets' primary receiver once he returns. He's listed 323rd in the lobby.

Newly acquired wide receiver Anquan Boldin is found 349th in the app, and Denver Broncos rookie running back De'Angelo Henderson is found at 361.

Training camp standout Kenny Golladay, rookie wide receiver for the Detroit Lions, is listed 298th. Jaelen Strong (511) and Braxton Miller (395) could be worth fliers while Will Fuller misses the first few weeks of the season.

Josh Gordon is listed 341st.

The athletic Matt Breida is one of the final players in the lobby at 805th. He's had some buzz in the San Francisco 49ers backfield this offseason.