To some extent the Ring tempts according to its victim's own desires which it merely magnifies and twists: Sméagol was already greedy and vengeful, albeit in a small, mean way -- the Ring took that and worked with it.  Sméagol murdered his cousin for desire of the Ring, but he then knew to use the Ring for no other purpose than to filch from his relations and to frighten them.  When his family drove him away, Sméagol crawled into a cave; and used the Ring to help him murder Orcs by grabbing them from behind.  In the RotK, when Sméagol fantasises about how he might prosper with the Ring's help, his aspirations go no higher than living in a place where he can eat fish thrice a day.  The Ring never put anything into Sméagol's heart -- it just brought out whatever was already there and twisted it to its own purposes and so enslaved the hapless Sméagol rather quickly.  Yet because of the limits of Sméagol's ambitions, the Ring stayed in a cave for five centuries. 
     Bilbo meanwhile, when he found the Ring, had rather different things in his heart from those which Sméagol had.  Bilbo took pity on Gollum and declined to kill him when he had a chance.  Bilbo used the Ring to save the Dwarves first from the Spiders and then from the Wood-Elves.  Bilbo followed very different impulses -- and, most importantly, never desired wealth or power over others.  So the Ring took a longer time to acquire a hold on him -- so long, in fact, that Bilbo was still able to give the Ring away freely (though it took a great effort of will on his part). 
     If, however, Bilbo had kept the Ring longer, it would, eventually, have gained enough control and would have used what baser instincts Bilbo had in doing so.  Eventually, it would have reduced Bilbo to its slave as it had Sméagol. 
     For the Ring always worked with what it found in its victim's heart: When Sam wore it in Cirith Ungol, it tempted him with a vision of turning Mordor into a blossoming garden which he could tend.  Boromir it tempted with the hope of using it to save Gondor -- with himself, personally, as the great hero; the one who singlehandedly would save Gondor, and would command its armies, and conquer Mordor and rule it...  The Ring always works with its victim's desires and twists them.  What the wearer has in his heart affects what the Ring can do.

Having talked some sense into Faramir (who had agreed to let Frodo and Sam go), the Fox was somewhat impatient to begin the journey to the Crossroads and wished that the Hobbits would hurry up.