The short answer is no.
The long answer is that you need to make sure all apps
are compatible with Mountain Lion. If your current OSX
is 10.6.x, you need to make sure that none of your apps
are still PPC based as emuation for PPC apps was dropped
in OSX 10.7 and 10.8.
Also, you should also make sure that any hardware you have
that required the installation of drivers have the latest driver
version installed and also that the drivers are 10.8 compatible.
If upgrading from 10.7.x and all was working well with it, then
most of the above mentioned should not be an issue but should
check anyway.
Also, be sure to backup any and all data that is important (cloning
current system to external drive would be ideal) as anything can
go wrong.