For whatever reason, this is a staple card in Commander. Quit it.
For those, who don’t know, I’m talking about this card:
[draft]Sensei’s Divining Top[/draft]
Its actually banned in Modern, which gives it an air of being powerful, but that’s not the reason its banned. Its banned for two reasons: It combos with [card]Counterbalance[/card] (a combo often seen in Legacy, where many decks only play cards with converted mana cost of one or two) and it slows down the games to a crawl. For these reasons, it was preemptively banned when the format first became sanctioned. Not because someone was afraid of people seeing two extra cards in their deck.
Top does give you a sense of control. You can choose what you draw next. Sounds fine, but its actually not that big of a deal. Think about it this way: You first use one mana to cast it and then one mana each turn to activate it. Sometimes more, sometimes less.
Alternative way of being able to access cards two cards deeper in your deck: A common card printed in seven different sets, [card]Divination[/card]. It costs you one card and three mana, meaning its quickly cheaper than the Top. You get two extra cards and now have access to the third card. No matter how often you activate the Top, you’ll never get any deeper into your deck than this most basic of card draw spells.
So, don’t put Top into your deck just because. People have been down on it lately, but some still cling to it, playing it in every deck without putting much thought into it.
Of course, there are reasons to play it. Mostly a heavy artifact theme or a lot of shuffling effects. Its a cheap artifact which can be animated (with, say, [card]Ensoul Artifact[/card] or [card]Tezzeret, Agent of Bolas[/card]), for example. Also, if you shuffle, you reset what you see on the top of your deck, so perhaps the effect could be worth a card, if you annoy your opponents with cards like [card]Thawing Glaciers[/card].
However, there are better options. [card]Crystal Ball[/card], for example, costs more to play and for a reason. At least you get to push those unneeded cards on the bottom of your library instead of having to look at them during each Topping, again and again, possibly being forced to draw some of them, because there aren’t better options.
Also, a new interaction would be all the manifest cards. You might want to know what you are manifesting before you do it. And then there’s [card]Oracle of Mul Daya[/card] and [card]Courser of Kruphix[/card].
Plenty of reason to play Top, but you should still want to put it in your deck with specific synergies in mind, not because you happen to own one (or several).