Microsoft Lumia 550 Mobile.....sliding To Answer

[Animals4me]

Just got the above mobile.All seems fine as had windows mobiles before.But am having trouble sliding up the bar when a call comes in as it won't slide up quickly so of course no time to answer and it goes to voice mail. But no problem when I want to power off and turn off with sliding down. Any suggestions please.
Wish there was just 2buttons,one to accept the other to tap on to decline which would be quicker and successful.
Hope someone sheds light on this.Anything you like or dislike about your lumia550. Thanks for all help and tips to use of it and anything that you can advise me of. Is it essential in setting up a Microsoft account?Will be interested in other owners views.....much appreciated any help