If you are a beginner and are getting off a chair lift, it can be recommended that you hang on to the chair for a while once your board touches the snow. This has several advantages;
you get increased stability because you can use the chair as a support, and when the small hill that the chair deposits you on actually starts sloping downwards, you can push off from the chair, thus increasing your speed, which is good since it brings added stability.
And finally, if you travel in a chair lift that's otherwise packed with skiers, there is a good possibility that they will have gotten so far ahead of you once you let go that you have space to maneuver around in.
The last point may not seem that important, but experience has shown me that some skiers tend to forget that they have a snowboarder right beside them since they're looking forwards and can't see the snowboard because it's shorter than skis.
This means that they may steer into you space or place their skiing poles in your path. Also, you need more space for braking than they do.
Either way, I find getting off a chair lift one of the easiest things to do on a snowboard. It can be tricky to brake though, given that your rearmost foot is just standing on the anti-slip area of the board.