Just a short note to myself: I found the following snippets useful when debugging telepathy.

# When debugging via SSH prepend with: DISPLAY=:0
# All run as user.
# First step: see what's going on on dbus.
dbus-monitor
# Debug gabble (jabber/XMPP).
# GABBLE_LOGFILE should be optional.
GABBLE_LOGFILE=/tmp/gabble.log GABBLE_PERSIST=1 GABBLE_DEBUG=all G_MESSAGES_DEBUG=all /usr/libexec/telepathy-gabble
# Debug mission control.
G_MESSAGES_DEBUG=all MC_DEBUG=1 MC_TP_DEBUG=all /usr/libexec/mission-control-5