Megson's time at the Reebok Stadium came to an end last December after his side's 2-2 home draw with Hull - a game in which they had led 2-0 - proved the final straw for disgruntled supporters.
Jaaskelainen told the Bolton News: "The Hull game was the low point. We drew the game 2-2 after being 2-0 up.
"He made a couple of changes at 2-1 and we were still cruising, but suddenly everything turned.
"It wasn't very nice, but if that's what the fans want, that's what they will do. That's why they come and pay, and we have to respect them.
"But that was a key point for getting a new manager. Gary Megson was never suitable to the fans and that was why we got a new manager.
"The fans are happy now, and that's the key thing and gives the players the confidence to enjoy their football.
"Since the new manager came in, the players have had confidence and he gets the best out of them. He knows how to manage players."
Under new boss Owen Coyle, Wanderers finished the season in 14th place in the Premier League table - nine points clear of the drop zone.
They will hope to build upon that in 2010-11, and Jaaskelainen is certainly expecting more from himself amid a more positive atmosphere.
He said: "I personally expect a little bit better from myself next season.
"If I look at the whole picture, I'm a little disappointed. I started all right, but Christmas was tough.
"It's not easy going into a game when, I wouldn't say we were getting abused, but people are not happy with the manager.
"It does play on your mind. The fans put pressure on the players and, in the position we were in, it was difficult.
"When the new manager came, things changed and it was a very enjoyable second part of the season."