Buffon, 40, captained Juventus to a seventh straight Serie A title and fourth consecutive Italian Cup triumph this season.
"To end this adventure with two new victories was important," the Italian told a press conference at the Allianz Stadium.
Italy's most capped player with 176 appearances, Buffon also confirmed he would not play again for the Azzurri, ruling out an expected international farewell on June 4 in a friendly against the Netherlands.
The former Parma goalkeeper will make his 640th Serie A appearance against Verona on Saturday.
Italy defender Giorgio Chiellini will take over the role of captain.
Buffon said he would like to take more time to reflect on his future, which could be either on or off the pitch.
"What am I going to do? Saturday, I'm playing a match and it's the only thing that's certain," he continued.
"Until 15 days ago, I was sure to stop playing, but I received some exciting proposals, both on and off the pitch. Off the pitch the most interesting was made to me by [Juventus] president [Andrea] Agnelli."
"Next week, after a few days of calm reflection, I will make a definite and certain decision."
According to the Italian press, Buffon has received offers from top European clubs including Liverpool, Real Madrid and Paris Saint-Germain.
"I'd like to get out of my comfort zone and to test myself in more complicated situations that I don't know," Buffon said.
"That's a way of seeing what you're made of and I've never been afraid of a challenge.
"I'm certainly not someone who thinks it's right to end my career in who knows what third or fourth division.
"I am a competitive animal and I won't be able to live or feel at ease in that situation.
"My fear was to reach the end of the Juventus adventure as someone who people just put up with or a player who had lost it."
It was a rollercoaster season for Buffon with Italy failing to qualify for the World Cup finals for the first time in six decades.
His final Champions League game ended in another fiasco last month as he raged into the night at the referee after being sent off late in a semi-final defeat by Real Madrid.
Buffon is facing a UEFA ban for his verbal abuse of English referee Michael Oliver, whom he said had "a rubbish bag for a heart".
European titles for both club and country are the only major ones missing from his collection as Juventus finished runners-up twice in the Champions League and Italy were beaten by Spain in the 2012 European Championships.
Italy career over
The 2006 World Cup winner has definitively drawn a line under his 21-year international career.
A tearful Buffon had called time immediately after Italy's World Cup exit in a play-off last November.
But his return to help the Azzurri in friendlies against Argentina and England sparked controversy for those who wanted to rebuild the team.
"As for the national side, If Buffon became a problem three months ago, I daren't think what he could be after three months or even six. Italy have some great, young goalkeepers who need experience," he said.
Buffon made his Serie A debut with Parma in 1996, winning the Italian Cup, Italian Super Cup and UEFA Cup before joining Juventus for €51 million in 2001.
He holds the record for going 974 minutes in Serie A without conceding a goal.
"His numbers are crazy: with Juve he has won 26 trophies, played 17 extraordinary seasons, 655 matches in total of which 300 without conceding a goal," Agnelli said.
But he is second for overall Serie A appearances with former AC Milan defender Paolo Maldini on 647.