I vote for the Hibiscus,

as you can get it to grow into a tree if it isn't already trimmed to look like one. They come in many colours & even double flower varieties.
Rio & laker love the Hibiscus tree. Before I got Rio - Laker was afraid of it. Now they both hang out in it & nibble the leaves & race around inside.
I am allergic to the darn thing myself - get really nasty welts when i touch it at all & I do touch it a lot when I trim it every other month [ i wash up immediately afterwards & wash the cutters as well].
Trim it every month! -yes as mine is over 20 years old - has been re-potted a handful of times as well & the root ball has been reduced as many times [kind of a bonsai treatment, you might say]
They grow quickly & can get quite bushy - so i also get rid of a lot of leaves so the birds have more play area. The Hibiscus loves to be misted every morning & love the west light - then they'll flower for you almost constantly. Mine hasn't flower much in the past 15 years as it lacks the proper light & I often forget it. If the leaves droop then it really needs water & if under stress like that they will not flower & if there are buds on it they will fall off.
Just don't over water it. The soil should never be wet for long - just damp. Make sure it is in a container that breaths - I have a pot that is glazed on the outside.
Another plant that is Idiot proof is the Mother-in-Law or Snake plant. If given a lot of light they will get almost 4' tall. They come in a variety of patterns but cuttings always seem to revert to the green/black stripe one. Rio loves this plant - he chews it a lot [the horrors of black stained beaks!] - once again it grows all the time so when a leaf.branch [they are only leaves like a giant grass] looks like lace - I cut it off. They grow like an Iris - they have running tubers & live in a bunch - the tighter the better. I water mine once a week or every other week - they are extremely tolerant. They can live in almost no light - but they get thin & short.
It's only short coming is that if you have it on the floor & you're vacuuming you can poke yourself with the top ends if you are daydreaming - honestly its happened to me! Cuttings root in water in about 4 days so you can have a forest in no time.