You should not get hypoxia at 10k, unless you have serious health issues, smoke, etc. If you do you should go to a doctor for a good check up because you are heading for big trouble.
Most people can spend hours a 10k with just tiredness and occassionally a headache.
Airliner cockpits are pressurised to about 8k, and there you are breathing pretty lousy air as well.
I agree flying high up is nice - on a clear day you get great views. I've done 18k. One needs an o2 kit for above about 11k; I can't remember the current CAA (G-reg) rules.